Chapter 1: When My Best Friend’s Sister Dared Me to Try Something

 

Early May, when the street trees were cloaked in fresh, vibrant green leaves.

The days after Golden Week had grown warm enough to break a sweat, but on this particular morning, the air still held a hint of chill as students made their way to school.

When Yuuma arrived at their usual meeting spot, he couldn’t help but exclaim in surprise at the transformed appearance of his childhood friend, Kousei.

“Kousei, what did you do to your hair?”

Kousei responded with a sheepish grin, though his pride was evident.

“Heh heh, I went to this salon Riko recommended. So, what do you think?”

“Abunaga recommended it? Man, you look completely different. I’m shocked.”

“Really…? It’s not weird, is it?”

“Nah, you actually look pretty cool. Well, at least appearance-wise.”

“Haha, shut up!”

Despite Yuuma’s somewhat detached response, Kousei didn’t seem to mind. He just grinned while fiddling with his phone.

Yuuma thought back to just a few days ago when he’d gone out with the usual group—Kousei’s sister Suzuka and her friend Riko—to check out the World Pudding Expo at Kingyo Mall, the largest shopping complex in the area (named after the local specialty of goldfish(Kingyo), which inspired its design). Back then, Kousei’s hair had been an unkempt mess.

Now it was cut short and dyed a lighter color. Combined with his naturally good build, he’d become quite handsome with a fresh, clean-cut look.

Lately, Kousei had started showing an unusual interest in his appearance.

He’d begun working out regularly and was constantly researching places popular with girls.

All this started after he’d taken a part-time job at a family restaurant to fund his gacha game addiction.

At first, he seemed to work reluctantly, just to pay for his game. But then one day, his attitude completely changed—he started heading to work with an obvious spring in his step. When he started saying things like “Older girls are nice, aren’t they?” and “A university student dating a high schooler is pretty normal, right?” and “A three-year age gap isn’t really that big of a deal, is it?”—well, it wasn’t hard to figure out what had happened.

It seemed he’d fallen for a female university student who worked at his part-time job.

Watching your best friend fall in love is somehow embarrassing, even if it’s not happening to you.

Yuuma let out an exasperated sigh, scratching his head uncomfortably.

Just then, a girl appeared behind Kousei wearing the same expression as Yuuma. Her long black hair, slightly disheveled from sleep, was forcibly gathered into two pigtails. She wore her blazer carelessly, her skirt remained at the regulated length without modification, and she gave off a plain impression with her complete lack of fashion sense.

This was Suzuka, Kousei’s sister and, like her brother, a longtime friend of Yuuma’s. She spoke with a weary tone.

“Onii-chan’s been like this since yesterday.”

“He’s totally love-struck.”

“He keeps asking if it suits him—honestly, what is he, a maiden?”

“Haha, to think this is our Kousei!”

Looking at Kousei now, he seemed unusually fidgety, perhaps conscious of the attention he was drawing.

Though he’d transformed so dramatically, he still couldn’t seem to muster any confidence. Yuuma and Suzuka exchanged knowing smiles.

Suddenly, Suzuka exclaimed “Oh, right!” and showed them something on her phone screen.

“Hey, doesn’t this look interesting? It’s the Ultra-Sized Rainbow Fresh Cream Super Sweet Honey Toast!”

“Ugh, I’m getting heartburn just looking at it! What’s with this ‘Challengers Wanted’ thing?”

“Come on, we’ve got to try this! Yu-kun, let’s go tackle it when we’re at our best!”

Unlike her brother who was caught up in romance, Suzuka was more interested in food than love. Her eyes sparkled with excitement as she tried to lure them toward what was clearly a sugar bomb waiting to happen.

Suzuka had always been driven by curiosity, often getting carried away with strange things like this.

Yuuma pressed his fingers against his temples as he replied.

“Hey, don’t tell me you’ve already forgotten about that tragedy at the hormone-yaki restaurant the other day?”

“Ahaha… what was it called again? Honeycomb and Senmai? Yeah, that stuff looked so grotesque, it took real courage just to put it in your mouth~”

“And we had no idea how long to cook it, so we ended up burning some pieces to a crisp.”

“But you know, it was kind of like morbid curiosity, and surprisingly tasty too! I actually want to try it again! But anyway, forget that—honey toast is where it’s at! This’ll be my first challenge as a sixteen-year-old!”

Suzuka, who had just celebrated her birthday last week, grinned mischievously.

Yuuma couldn’t help but smile wryly, imagining how he’d probably end up going along with her schemes again.

Noticing their conversation, Kousei looked up from his phone and cut in.

“Hey, what are you guys talking about?”

“Oh, just hoping that senpai from your part-time job will think you’re cool.”

“Onii-chan, try not to act too suspicious when you’re around senpai!”

“Wha-!? T-That’s not… I mean, this has nothing to do with senpai…!”

“Sure, sure.”

“…Ugh.”

“Hey, are you two even listening to me? Yuuma! Suzuka!”

The sudden shift to talking about his senpai made Kousei’s face turn bright red as he frantically tried to deny everything, while the others deliberately teased him in unison.

Watching their friend’s reaction, Yuuma and Suzuka raised their eyebrows and shrugged their shoulders with a “what can you do?” expression.

 

At their usual time, from their usual spot, the three of them boarded the train and rode it for three stops.

As the doors opened, a girl raised her hand in greeting as if on cue and stepped aboard. She wore the same uniform as Suzuka, though somewhat disheveled, and despite her small stature, she had a flashy presence. Upon seeing Kousei’s complete transformation, her eyes widened dramatically before settling into a mischievous grin.

“Heya~! …Whoa, no way! Kousei-senpai really did get a makeover!”

“Yeah, I went to that salon Riko recommended right away.”

“They’re good, right~? I mean wow, even THE Kousei-senpai looks presentable now… well, appearance-wise at least!”

“Shut up! Don’t say the same thing as Yuuma!”

“Tehe!”

The girl playfully teasing Kousei was Abunaga Riko. Being a year younger and Suzuka’s close friend since middle school, she was comfortable enough to hang out regularly with Yuuma and the others.

While Kousei was being teased by Riko, he couldn’t help but grin at the positive response to his makeover, which only led to more teasing from Riko in an endless cycle.

Yuuma and Suzuka exchanged knowing smiles at this familiar and somewhat endearing scene.

(Abunaga…)

As Yuuma furrowed his brow, considering her feelings, Riko finished teasing Kousei and bounced over, her skin practically glowing.

“Hey, Suzu-chan. You’ve got to admit, Kousei-senpai had good raw material to work with. He actually looks pretty cool now, right?”

“Yeah, I’m surprised too, even though he’s my brother.”

“Suzu-chan, why don’t we take you to the same place? Come on, let’s go! You’d look super cute!”

“Mm~ I’ll pass. It’s all just too troublesome.”

“Ugh, there you go again! Still rejecting your femininity! Kawai-senpai, say something to her!”

Put on the spot, Yuuma glanced at Suzuka.

Though her overall impression was plain, she had a well-proportioned figure and refined features.

Riko had a point—Suzuka had good natural qualities. With proper care, she could probably transform just as dramatically as Kousei had.

But Suzuka wore the expression of someone who’d heard this all before, looking somewhat troubled.

She’d probably been told similar things countless times.

Yuuma gave a wry smile as he replied.

“Maybe so. But in the end, it’s her choice.”

“Aww, what a waste! I mean, even Kousei-senpai managed to transform!”

“Yeah yeah, even Riko, who was such a messy-haired kid in middle school, looks like this now.”

“Nngh-! Kousei-senpaiii!”

At Kousei’s retort, Riko puffed her cheeks and raised her fist, as if warning him not to bring up her past.

Back in middle school, Riko had been the complete opposite of how she was now—her eyes hidden behind her bangs, her hair in plain braids, and her skirt so long you couldn’t even see her knees. She’d been a gloomy, unfashionable sight.

“Ooh, scary, scary!”

“Geez!”

“Haha!”

“…Sigh.”

Everyone laughed at the familiar scene unfolding again, but Yuuma quietly averted his weary gaze from the pair.

After parting ways with the underclassmen Suzuka and Riko at the school entrance, he headed to classroom 2-1.

“Morning!”

“Hey there!”

“Yo… Wait, Kuramoto, what happened to your hair!?”

“No way, is that really Kuramoto!? I didn’t recognize you for a second!”

“Well, actually, my junior gave me some advice—”

The moment Kousei opened the door with his greeting, he was immediately surrounded by classmates.

It was only natural.

Until now, Kousei had been like Yuuma—plain and unremarkable. Just another face in the classroom crowd.

And then, right after Golden Week, he showed up looking completely stylish. It would have been harder not to be curious.

Classmates gathered around him from all directions, bombarding him with questions like “What brought this on?” “Do you have a girlfriend!?” “You’ve got to introduce us!”

Kousei’s flustered responses of “N-No, it’s not about a girlfriend!” and “I-I just wanted to look more presentable for my part-time job…” only served as unintentional confessions. The excitement continued to build.

Yuuma quietly made his way to his seat, trying not to disturb the commotion around Kousei.

As he set down his bag, he couldn’t help but overhear the girls’ whispered conversations.

“Isn’t Kuramoto-kun totally different!? Talk about a dark horse!”

“He’s not bad at all, might actually have a chance! I’m single right now too…”

“Hey, what happened with that guy from Nishi High?”

“Oh, that? Whatever. What about you and that guy from the next class?”

“Oh my gosh, tell me everything!”

Listening to their chatter, Yuuma’s face twisted into a grimace.

Everywhere he looked, Kousei’s transformation had sparked nothing but talk of romance.

Well, that was high school for you. It was only natural to be interested in the opposite sex at this age.

This scene was probably playing out in classrooms all over the country.

(…!)

A bitter feeling seeped into Yuuma’s chest. He let out a sigh, trying to expel it as he quietly left his seat. The atmosphere in the classroom today just didn’t sit right with him.

 

After school came to an end.

The classroom had been abuzz all day with talk about Kousei and various romantic entanglements.

Having spent an uncomfortable day surrounded by all this, Yuuma was hurriedly packing his bags to head home as soon as the bell rang when he heard a familiar “Hey.”

“Kousei?”

“Um, Yuuma… are you free after this?”

“Nothing particular planned.”

“Then… want to stop by my place on the way home?”

“…Sure.”

Kousei’s invitation came with unusual hesitation.

After spending the whole day immersed in talk of romance, Yuuma wasn’t so dense that he couldn’t guess what lay behind this invitation.

With a wry smile, he left school alongside his longtime friend.

Usually, they’d chat about nothing in particular on their way, but today Kousei seemed restless and remained completely silent.

“Go ahead to my room. I’ll grab us something to drink.”

“…You don’t need to be so formal about it now…”

“Just go with it.”

As soon as they reached the Kuramoto house, Kousei hurried to the kitchen to fetch drinks—something he rarely bothered with. Yuuma raised an eyebrow as he headed to Kousei’s room.

The last time he’d been here was before the holiday break, when they’d celebrated both Kousei’s seventeenth birthday in April and Suzuka’s sixteenth birthday in early May together. They’d been visiting each other’s rooms since elementary school, and Kousei’s room felt like a second home to Yuuma.

He knew where to find every game, manga, trinket, figure, and piece of stationery in this room. It wasn’t unusual for him to retrieve things that the room’s owner himself had forgotten where he’d put.

That’s why it felt so jarring to see men’s skincare products, cologne, fortune-telling books about love, and women’s magazines featuring dating advice scattered around the room.

Sitting down somewhere convenient, he picked up one of the magazines and grimaced as he read aloud.

“‘Don’t miss the signs that they like you’… talk about clickbait. ‘Use words that make them conscious of you,’ ‘Maintain appropriate distance based on the situation,’ ‘Don’t push your feelings without considering their pace’… I mean, it’s good advice, but isn’t this a bit much for beginners?”

Yuuma couldn’t help but comment sarcastically. He smiled wryly, imagining his friend—whose emotions were always written plainly on his face—trying to play these subtle romance games.

(His senpai probably already knows he likes her.)

As he was flipping through the pages with these thoughts, he heard “Sorry for the wait.”

“Kousei…”

“Ah, er, that’s…”

Noticing the magazine Yuuma was reading, Kousei’s eyes darted around nervously, his behavior becoming suspicious.

After standing awkwardly in the doorway for a while, Kousei seemed to steel himself, muttering “Alright” as if to boost his courage. He set down a tray with glasses in front of Yuuma and plopped down cross-legged across from him.

Scratching his cheek sheepishly with his index finger, he began to speak.

“So, uh… surprised to see all this un-Kousei-like stuff?”

“Well, yeah. None of this was here last time, so it’s pretty shocking how it doesn’t suit you at all. But considering your hair today, I guess it makes sense… looks like it’s working.”

“O-Oh, you think so…? Hey, what do you mean it doesn’t suit me!?”

“Haha, just hope this new coating doesn’t peel off too quickly.”

“S-Shut up!”

Kousei scratched his head embarrassedly at Yuuma’s teasing.

They shared a laugh for a moment.

Then Kousei cleared his throat and put on an unusually serious expression.

Yuuma straightened his posture, sensing the main topic was coming.

“Well, um… actually, there’s someone I like.”

“…I see. It’s that senpai from your part-time job, isn’t it?”

“Y-Yeah… But this is my first time feeling this way… I have no idea what to do. You’re the only one I could talk to about this…”

“You know I’ve never had a girlfriend either, right? I can’t give you much advice.”

“Even so—ah, hold on a second.”

Just then, Kousei’s phone buzzed with a notification. The moment he saw the name on the screen, his face lit up like flowers blooming, and he eagerly tapped to answer the call.

“Hello, Kuramoto speaking, senpai! Eh, a sudden vacancy? My plans? No, no, I’m completely free right now! Should I come in now? Yes, yes, I’ll be right there…!”

It seemed to be from his crush.

Yuuma asked with a wry smile.

“Work calling you in?”

“Yeah, they need emergency help. Sorry, Yuuma, I know you just got here…”

“It’s from your beloved senpai, right? Just go already.”

“I’ll make it up to you, I promise!”

“Don’t worry about it.”

Thrilled at being needed by the person he liked, Kousei rushed out like a whirlwind, practically skipping with joy.

Yuuma watched his clearly elated friend leave, squinting as if the sight was too bright to look at directly, then muttered under his breath with disgust:

 

“Love… what nonsense.”

 

His face twisted into a grimace as he ground his back teeth.

After a moment, he relaxed his tensed body and let out a heavy sigh.

Left alone and at a loss in Kousei’s room, Yuuma collected his thoughts and considered what to do.

In the past, even when the room’s owner wasn’t around, he’d often kill time playing games or reading manga. But now, with so many unfamiliar items around, he felt uncomfortable.

The unusually formal tea service sat lonely on its tray.

Just as he was reaching for it, a voice called from the open doorway.

“Oh, Yu-kun!”

It was Suzuka, still in her school uniform—she must have just gotten home.

“Welcome back, Suzuka.”

“Tea, huh? That’s rare… Where’s Onii-chan?”

“He just rushed off to work, practically dancing with joy.”

“The famous senpai?”

“Yep, that senpai. He actually came to me for advice today about falling for her.”

Yuuma shrugged his shoulders in exasperation, while Suzuka’s eyes widened in surprise.

“Eh? Onii-chan actually talked to you about it?”

“Well, it was obvious from his behavior anyway, so it wasn’t much of a revelation.”

“I guess~ But it’s funny—he absolutely refused to admit it to me, even though he made me buy all those magazines.”

“Half of those were jokes, weren’t they? Like ‘Special Kiss Feature: Creating the Mood and Solo Practice Methods’?”

“Ahaha, busted! But I never expected to catch Onii-chan actually practicing kissing on the back of his hand, or running back and forth to the kitchen for ice to practice moving his tongue!”

“Haha, well, I guess that shows how serious he is about her.”

“Yeah… getting all worked up over love and stuff, it’s really—

 

—so stupid.”

 

“……………………Suzuka?”

Yuuma’s eyes widened at Suzuka’s dismissive words, and he studied her intently.

Realizing she’d accidentally revealed her true feelings, Suzuka made a guilty face and tried to cover it up with an “Ah,” letting her eyes wander for a moment.

Finally, as if resigned, she let out a big sigh and sat down next to Yuuma, speaking haltingly.

“You know how they talk about the three-month wall?”

“Yeah, that thing about breaking up and all.”

“Right, right. Well, we’re at that age, you know? Girls are always talking about who likes who and who’s dating who. Ri-chan loves that kind of talk too.”

“Yeah, Abunaga’s always excitedly giving Kousei advice too.”

“But most couples break up pretty quickly. ‘We only dated out of curiosity,’ ‘They weren’t what I expected,’ ‘I put up with it for status but I can’t anymore,’ ‘He dumped me because I wouldn’t sleep with him since he thought I was easy’… all sorts of reasons.”

“That does happen a lot.”

“People just follow their momentary feelings, and someone they claimed to love just yesterday becomes someone they’re badmouthing the day after breaking up. And they never think about how it affects everyone around them. Really, what’s the point of dating? Why would you want to mess up relationships just for that? I don’t want to make those kinds of mistakes.”

Suzuka’s contemplative words resonated deeply with Yuuma.

Suddenly remembering his own bitter experience, he spoke with a hint of self-mockery.

“Mistakes, huh… I’ve made my share too. I took someone’s penalty game teasing seriously and got hurt pretty badly. Since then, I’ve had some thoughts about romance.”

“Eh, no way, that happened to you!? I never knew about this!”

“Yeah, well… I haven’t even told Kousei about it.”

“Hmm… So what did you like about this girl? Was she cute? Did she have big boobs!?”

“The cheerful pretty type? She’d touch me a lot, we had good conversations, and yeah, she was well-endowed… I won’t deny I was pretty smitten.”

“Ahaha, so you were seduced by her charms. You’re such a boy, Yu-kun!”

“Shut up! Can’t help it! At that age, of course I was curious…”

As Yuuma puffed out his cheeks and looked away in embarrassment, Suzuka patted his shoulder consolingly, then spoke with a knowing smile.

“Now, now, Yu-kun. It’s not like us girls don’t have our own curiosities about boys.”

“Really?”

“Yeah, like ‘His hands are so big, I bet it’d feel nice to be touched gently,’ or ‘That actor has such nice muscles, I want to be held by him,’ or ‘That guy we saw on the street had such sensual lips, I wonder what they’d feel like’… we talk about stuff like that too!”

“Huh, that’s kind of surprising…”

“When you get down to it, dating someone ultimately leads to one thing, right? There’s even that phrase about physical compatibility. Though in my circle, everyone gets caught up in drama before they even get that far. Such a pain.”

“I see.”

Yuuma smiled wryly, both surprised and agreeing with Suzuka’s oddly philosophical yet practical view that romance was essentially just a process leading to physical intimacy. It was a very Suzuka-like way of thinking—direct and unvarnished.

“Don’t you guys talk about this stuff? Oh, and we girls talk about boobs a lot too. I mean, you can see them right away. But me, even if I push them up, there’s barely anything to grab. I wish I had at least as much as Ri-chan.”

Saying this, Suzuka put her hands on her chest, frowning as she squeezed her modest breasts through her uniform.

Yuuma blinked in surprise at this sudden action from his best friend’s sister, but found himself speaking honestly.

“Well, size doesn’t matter really. I guess guys are just drawn to them because we don’t have them.”

“Want to feel mine then? They’re all-natural A-cups! Room for growth—I’d at least like to be a B-cup!”

“H-Hey, don’t tease me like that!”

“Oh, you’re blushing! I didn’t think even you would get embarrassed about me.”

“…Geez.”

Suzuka giggled cheerfully.

Though they’d always been able to talk about anything, they rarely discussed such sexually-charged topics since entering middle school.

But once they started talking, she seemed to get carried away, saying in an obviously exaggerated voice, “But really, it’s so sad how little I have…” while pressing her small chest against Yuuma’s arm.

Though she claimed there wasn’t much there, he could definitely feel a soft sensation that made his heart race unexpectedly. He couldn’t bring himself to push her away.

The atmosphere was becoming increasingly strange.

As Yuuma struggled to find something to say, his eyes fell on the magazine spread out on the table.

Catching sight of the words about the kiss special feature, Suzuka murmured quietly.

“…They say kissing feels good.”

“…So they say.”

Yuuma nodded solemnly, aware that he was being swept up in the mood.

They both looked at the magazine’s kissing feature.

As they read about creating the right atmosphere, timing, and how to give signals for a kiss, Suzuka’s fingertips suddenly brushed against the back of his hand.

Startled, Yuuma’s shoulders jumped slightly as he looked at her.

Her eyes were slightly moist with curiosity as she whispered like she was suggesting some mischief.

“Is it true?”

“Who knows?”

“Want to try it?”

“N-No, wait… that’s… we shouldn’t…”

Yuuma was shocked by Suzuka’s sudden proposal.

No matter how curious she might be, this wasn’t something they should just casually do.

“Come on, it’s not like it would be our first time.”

“That was when we were kids—mmph!?”

“Mm… chu.”

As he was about to protest that it was different from when they were children, she suddenly pecked his lips.

Yuuma’s eyes went wide while Suzuka just gave him a mischievous smile, running her tongue over her lips as if savoring a treat.

A shiver ran down Yuuma’s spine.

“We really did it.”

“…Suzuka.”

“Though that felt more like our teeth bumping than a kiss. Hey, let’s try again.”

“Mm…”

Suzuka pressed her lips against Yuuma’s again, as if testing the sensation.

Then she pulled away, furrowing her brow as she mumbled.

“It’s kind of… soft? Such a strange feeling. As for whether it feels good—”

Yuuma’s head was spinning.

As if some switch had been flipped inside him, he took Suzuka’s hand that had been lightly touching his, interlacing their fingers as if to keep her from escaping, and this time he was the one to press their lips together.

“Mmchu… mm…”

While gently sucking on her lips, he savored the plumpness of her bottom lip.

He hadn’t noticed when he was on the receiving end, but Suzuka’s lips were incredibly soft.

These were different from his own—they were a girl’s lips.

This was nothing like the innocent kisses they’d shared as children out of curiosity.

As if possessed, they lost themselves in the moment, forgetting to breathe as they sought each other’s lips again and again.

When they finally separated for air, their heavy breathing echoed through the room.

“…Geez, that was so sudden. So, how was it? Did it feel good?”

“…I’m not really sure.”

“Maybe it’s supposed to be french kissing that feels good? You know, with tongue.”

“Is that right? …Though I don’t know how to do that.”

“…According to the magazine, you’re supposed to gently slip your tongue just past their lips. Want to try?”

“No, that’s going too far…”

He could justify simple lip kisses—even if he’d gotten carried away earlier, they’d done that much as children playing around.

But french kissing would definitely cross the line beyond innocent play.

Yuuma made a troubled face.

Suzuka let out a little “hmph” through her nose and whispered provocatively.

“What, don’t tell me Yu-kun is scared?”

“That’s not it.”

“Then prove it.”

“Mmph…”

Though he knew it was childish, Yuuma furrowed his brow, not wanting to feel like he’d lost to Suzuka’s challenge.

He gripped her shoulders firmly and, instead of replying, pressed his lips against hers again.

“…mm”

“Mmm… mm!?”

The moment he slipped his tongue inside, Suzuka’s shoulders jumped and her eyes went wide.

Though Yuuma hesitated for a moment at her reaction, he cautiously traced along her gums and the inside of her cheeks, and gradually Suzuka’s eyes grew dreamy.

When he gently knocked against her teeth with his tongue tip, she opened slightly, and as she squeezed their still-joined hands, Yuuma took it as a signal to venture deeper.

“…ah”

As their tongues met, a strangely sensual sound escaped Suzuka’s lips—a tone he’d never heard from her before.

Yuuma’s mind went blank as an irresistible, primal urge took over, and he focused solely on the movement of their entwined tongues.

“Mm… nn”

“Chu… mm…”

Their bodies grew impossibly hot, as if melting and merging into one.

The room filled with nothing but the wet sounds of their passionate kisses and heavy breathing.

They couldn’t think of anything else.

—PON ♪

“Mmph!?”

“Pwah!”

Just then, Suzuka’s phone chimed with a notification. The two sprang apart as if shocked.

“W-Who is it?”

“R-Ri-chan! A message about cream puffs or something…”

“I-I see.”

“Y-Yeah.”

Their conversation died there, leaving behind an awkward yet frustrating atmosphere.

“……”

“……”

They had been completely caught up in the moment earlier.

But their bodies were still hot.

They could clearly feel the desire to continue where they’d left off.

They stole glances at each other’s flushed faces.

“…That was intense earlier.”

“…Yeah, it was really something.”

“Did it feel good for you, Yu-kun?”

“Well, we got interrupted before I could really tell.”

“The magazine showed even more stuff after that part.”

“Yeah, like embracing and entwining tongues more intensely.”

“Haha, but it’d be bad if someone caught us trying that stuff.”

“True. And Kousei’s room has a broken lock.”

“……”

“……”

“Then… want to come to my room?”

“…………Yeah.”

Yuuma could only nod at Suzuka’s invitation.

Trying to contain their eagerness, they headed to her room.

As soon as they entered, they embraced impatiently, their tongues and bodies intertwining passionately.

Suzuka’s body was slightly damp with sweat as he caressed her, and the sweet scent rising from her made Yuuma’s head spin, melting away his reason.

His consciousness grew hazy.

“Hah… mmn… chu…”

“Mmn, nn… hah… nn…”

Suzuka in his arms responded amazingly to his advances.

It felt like he was gradually dyeing her in his own colors.

“Mmm~, pwah!”

“…!?”

Suddenly, Suzuka’s shoulders trembled and her weakened body collapsed against him.

Between heavy breaths, she spoke with slight embarrassment.

“…Wow. My legs gave out. Kissing really does feel good.”

“…Yeah.”

The familiar sight of Suzuka being shy suddenly seemed incredibly cute.

His instincts whispered to connect even more deeply.

But having pulled away for a moment, Yuuma regained a bit of his reason and understood just how dangerous this situation was becoming.

If they continued like this, he’d give in to his desires and end up taking his best friend’s sister’s innocence.

Yuuma gripped Suzuka’s shoulders and pushed her slightly away, speaking almost pleadingly.

“Suzuka, we should stop here.”

“Eh… Yu-kun, didn’t it feel good?”

“The opposite. It feels too good—I don’t know what might happen if we continue.”

“Oh~?”

Though he’d meant to be considerate of her, she looked somehow pleased, and whispered with a bewitching expression he’d never seen before.

“It’s okay if it’s you, Yu-kun.”

“…What do you mean ‘okay’?”

“I’m curious about what comes next too, and we’ll experience it someday anyway. So…?”

“Suzuka…!”

Her words suggesting they continue shook his mind, making him dizzy. Though he called her name sharply as if scolding her, she only replied with a provocative smile.

“Yu-kun, you’re trying to hold back, but aren’t you at your limit?”

“—Stop! If you say anything more, I’ll really—”

With a mischievous giggle, Suzuka caressed Yuuma’s tightly-wound instincts, bringing her lips to his ear to whisper enticingly.

“I said it’s okay—if you can do it.”

“Suzuka!”

“Ahnn♡”

Those words were the trigger that made Yuuma lose all reason.

When he came back to his senses, the setting sun streaming through the window had dyed Suzuka’s room crimson.

In this functional, unfeminine room, their heavy breathing echoed as if from far away.

“You beast, Yu-kun. Even when I said it hurt…”

Suzuka’s muffled, reproachful voice came from where she had buried her face in the pillow.

—Ah, she was absolutely right.

Yuuma looked down at Suzuka’s exposed form before him, his face contorting with the realization of what he’d done.

Her disheveled uniform and exposed white skin, marked by his desire.

The bed sheets bore a deeper red than the sunset—the proof of their first time.

An awkward atmosphere filled the room, along with the distinct scent of their mingled intimacy.

Any way you looked at it, these were the aftermath of their deed.

—He’d done it. He’d actually done it.

In a gloomy mood, Yuuma sat up, averting his eyes as he silently fixed his clothes.

Even if she had provoked him with that challenge.

Even if they had both been caught up in that strange atmosphere.

Still, when he’d actually crossed that line, he had truly become the beast Suzuka called him, completely devoid of reason.

His heart was filled with deep regret and guilt.

And alongside that guilt dwelled a dark desire to devour her body again and drown in pleasure.

This was absolutely the worst.

But he didn’t even have the courage to look back at what he’d done, falling deeper into self-loathing.

If he stayed in this room any longer, he felt like he might lose control again.

“Sorry, I’m going home now.”

“…Ah.”

He somehow managed to force out those words, shaking his head slightly as if to clear away the swirling emotions, and fled the room like he was running from Suzuka.

He rushed out of the house and leaned against the entrance, letting out a deep sigh as if expelling something from his chest.

On this day, Yuuma had crossed a line with Suzuka, his best friend’s sister whom he’d known since childhood.

Walking home with unsteady steps like a wandering ghost, Yuuma recalled how everything had unfolded and sank into self-hatred.

You could say it had been consensual.

But it was also true that he’d given in to his desires and defiled his childhood friend’s sister.

In that moment, he had truly been nothing more than a beast.

 

“…How am I supposed to face her tomorrow?”