That night, after Kazuto had taught her various things about sex.

Alone on the bed in her room, she slowly slid her hand down to her lower abdomen.

“Uh… n-ngh… ah…”

Her fingertips trembled slightly as she relentlessly toyed with the swollen nub, slick and wet with overflowing fluids.

The more she touched it, the more heat spread throughout her body, clouding her senses.

“Fuka… se… kun…”

Even if it had only been a simulation, the sensations of Kazuto’s body pressed tightly against her and his crotch pushing against her own lingered in her mind.

If his thing had really gone inside her— 

Just imagining it was enough to send uncontrollable desire surging up from within.

Her left hand pinched her nipple directly, while her right hand intensely stimulated her thoroughly soaked private parts.

Kokonoe Touka was drowning in her own pleasure, replaying the events of the day over and over in her mind.

“——Nnngh… ah…! ♡”

After arching her body sharply, her legs trembled and twitched in the lingering afterglow.

Her mind went completely blank, everything being painted over by pleasure.

“Haa… haa… haa…”

Gasping for breath as she stared up at the ceiling, Touka slowly withdrew her fingers.

The only person occupying her thoughts was—Fukase Kazuto. 

“I want to… really do it with Fukase-kun… but Fukase-kun has Otomi-san… and I’m supposed to be help him get closer to Otomi-san… and yet, feeling like this… it’s bad… right…?”

Lately, Touka found herself thinking about Kazuto all the time.

At first, it had been nothing more than simple curiosity.

She wanted to know what men were and understand them. That was all it was supposed to be. 

◇◇◇ 

Today’s talk about sex didn’t just affect her. It had stirred another boy deeply as well.

“Ggh… ngh… ah…!”

His lustrous golden hair swayed slightly as his shoulders trembled. 

With his right hand, he kept rubbing up and down over his swollen lower body.

It was an act Kazuto had only taught him the other day.

At the time, he hadn’t felt any urge to actually try it.

But today, after hearing the specific details about sex, an uncontrollable curiosity surged up inside him.

In this world, it was considered impossible for boys to have sex with girls.

Yet Kazuto was already beginning to break that common sense.

If that was the case, then maybe he had a chance too… or so he found himself thinking.

“What is this… I never knew something could feel this good… But real sex must be even more intense, right…?”

The boy, Hareruya Aoi, was so overwhelmed by the pleasure that all strength drained from his body, leaving him wrapped in a sense of bliss.

“Ah… it’s shrinking… I think they call this the ‘sage time,’ right…? What a weird name…”

After reaching climax, he quickly regained his composure. 

Tonight was the first time Aoi had tried the act Kazuto had taught him. 

“…Can I be like Kazuto-kun too… and fall in love with a girl?”

Meeting Kazuto had drastically changed Aoi’s perception. 

Even before this, there had been times when simply looking at girls made his chest grow warm on its own.

But he hadn’t understood what that feeling meant or where it came from, and he couldn’t tell anyone.

And in the midst of all that, someone was approaching his room.

“Hey! Let’s play a game!!! …W-wait, w-what are you doing!?”

“O-onee-chan!?”

Bursting into the room without knocking was his older sister, a college student who’s five years older than him—Hareruya Midori.

“Your lower half is completely exposed… and this smell… what is this?”

“I-it’s not what you think, Onee-chan.. It’s just—” 

“……”

Without a word, Midori stepped closer, taking in the state of the sheets and Aoi.

“…Did that come from there, Aoi?”

“Ah… ugh…”

He couldn’t understand why he felt so embarrassed now. 

Being seen naked wasn’t anything new at this point.

When he was little, he’d even bathed together with his sister.

And yet, for the first time, an unbearable sense of shame came surging up in his chest.

“Aoi… your big sister is on your side.”

Gently lowering herself beside him, Midori met his eyes with a soft gaze.

“It must be tough out there, right? But to me, you’re always my cute little brother. So… if there’s something you want to talk about, I want you to tell Onee-chan.”

Her gentle voice and gestures eased the tension in Aoi’s shoulders.

Midori, like Aoi, was beautiful and had always been popular.

And now, his sister’s gaze had turned serious.

“B-but…”

“If it’s about you, Aoi, I’ll accept everything. Okay?”

“…………”

Pressed for an answer, Aoi fell silent, lost in thought.

For a moment, the urge to at least put his underwear back on crossed his mind, but he couldn’t bring himself to avert his eyes and run away anymore.

“…Will you believe what I’m about to say?”

“Yeah. Of course.”

“You might think I’m lying. But if you’re willing to hear me out, then…”

Aoi trusted Midori and began to speak.

He left Kazuto’s name out, but told her about how a male friend he had grown close to had taught him about sex and masturbation.

And then, he honestly conveyed that he had actually tried it himself.

“…It’s hard to believe right away, but if you’re saying it, then I know it’s true.” 

“All of it is true. When I actually tried it… it really felt good…” 

Midori’s gaze was naturally drawn to Aoi’s lower body.

Her younger brother’s body had matured before she realized it.

Seeing that change with her own eyes, she caught her breath.

Seeing that change with her own eyes, she caught her breath.

Seeing that change with her own eyes, she caught her breath.

“…That’s what they call a penis, right?”

“Yeah. I think the name is kind of strange, though.”

“Hehe, definitely. And when you move your hand up and down or licking it makes you feel good, right?” 

“Y-yeah…” 

She couldn’t fully grasp it through words alone

Yet the sight before her eyes was undeniable proof of at least one thing.

A rich scent tickled her nose, causing Midori’s breath to grow ragged.

“S-should I… do it for you?”

“O-onee-chan?!” 

“Look, there aren’t many things you can really enjoy, right, Aoi? …So, if there’s anything your big sister can do to help… I’d really like to do it for you.”

“B-but… we’re siblings…”

“You don’t have to worry about that. I even know people who do things like this with their sisters.” 

Faced with the unbelievable proposal, Aoi was left speechless.

Yet deep down, an uncontrollable curiosity began to stir.

If he were to let someone touch him… he couldn’t help but wonder how incredible it would feel.

“I-if you’re not against it, Onee-chan…”

“Of course I’m not. If it makes you happy, Aoi, that’s enough. Tonight. I’ll sneak into your room, so wait for me, okay.”

“…U-un.” 

After saying that, Midori left the room without bringing up playing games together.

Aoi remained frozen on the bed, staring blankly.

Is this okay between siblings?

He was still hesitant, but it wasn’t as if they were going to have sex. It was just foreplay.

After all, it was just like Kazuto said—nothing more than the preparation stage.

—So it should be fine.

That was what he believed at the time.