Doing something wrong with my childhood friend under the blue sky.

That sense of taboo only made it even more exciting.

“Mm...”

Chiyu gathered saliva in her mouth, then let it spill down into her cleavage without wasting a drop.

The softness of her breasts alone had already been enough to make me feel so good I might lose control, but now that slickness was added too, starting to work like lubricant.

The pleasure instantly jumped, and my hips tensed on their own.

If I just surrendered to it, I probably would not last even a few seconds.

She did not care about getting dirty, dropping to her knees on the ground with her upper body bare as she kept tending to me.

Each time she moved, the sensation changed, the pressure changed, and an indescribable pleasure rushed from my lower belly all the way up into my skull.

“Mm... mm, mm. So-kun’s gotten rock-hard because of me.”

My childhood friend understood my tastes perfectly, and she knew exactly what kind of words men liked to hear too.

But that line had probably been her honest opinion as well.

That was how overwhelming the effect of Energy Up was.

That said, if there had not been anything to excite me in the first place, I would never have gotten this worked up.

“It’s because your chest is so erotic, Chiyu.”

“If it makes So-kun happy, I’ll be as erotic as you want.”

Looking up at me with eyes as blue as gemstones, Chiyu said that.

Then her gaze dropped lower.

“W-wait, Chiyu, you’re not seriously—”

“Boys like this.”

She leaned in and kissed me.

And before I could stop her, the hidden break by the bath wall turned even more reckless.

Under the effect of Energy Up, Chiyu shamelessly used both her chest and her mouth in a way that was clearly tailored to my tastes, pushing me right to the brink with almost terrifying precision. The combination of the spell, the taboo of doing this outside in secret, and the sheer devotion she poured into it destroyed what little restraint I had left.

Chiyu did not pause for even a second.

It was not just the act itself. I could feel what was in her heart too.

That overwhelming affection—wanting only to give me the best possible pleasure—reached me just as clearly as the physical sensation, and all of it fed the heat building inside me.

There was no way I could hold out for long.

“Chiyu... I’m close...!”

She did not stop.

What followed blew away the last of my control. I climaxed quickly under her devoted attention, and Chiyu accepted everything without pulling away. When it was over, she even swallowed it all despite how clearly unpleasant it was, simply because she believed it would make me happy.

After everything had finally subsided, she slowly pulled away and opened her mouth toward me.

“Ahh...”

Even mixed with her saliva, it was obvious how much she had taken in.

Just seeing that was enough to send another jolt of excitement through me.

Then Chiyu closed her mouth and, unbelievably, began swallowing.

“W-wait, Chiyu...!?”

That might be a man’s dream, sure, but I knew perfectly well it was not something that actually tasted good.

I told her she did not have to force herself, but she kept staring straight at me as she slowly, steadily swallowed it all.

There had been so much that it took time. She had to do it in several gulps, and it took a full minute or two before she finally finished.

Only then did Chiyu open her mouth for me again.

Nothing was left now. She had swallowed it all.

“Cough, cough. I drank all of it. ...Doesn’t that make you happy?”

The uneasy look on her face made me panic.

“N-no, it does. Honestly, I’m ridiculously happy, and it’s turning me on like crazy, but... it tasted awful, ~Nоvеl𝕚ght~ didn’t it?”

There had not even been time for me to go soft in between.

I was still just as hard as before.

That was not only because of the spell. Chiyu’s actions were doing it too.

“Mm. Super awful.”

“Y-yeah... figures...”

“But... if it makes So-kun happy, I’ll do anything.”

“Chiyu...”

At her words, I twitched again.

My childhood friend did not miss that.

“Good. That looks happy too. Want me to hold you again? Or should I try just my mouth this time?”

As if it were the most natural thing in the world, Chiyu reached for me and started stroking while she asked.

She had helped me with her hand on the first night, but this was still only our fourth day on the deserted island.

And yet her rate of adaptation was ridiculous. Her growth was ridiculous.

My inexperienced childhood friend was acquiring a level of erotic skill in just a few days that would put a succubus to shame.

“I’ll devote all of me to So-kun. So become my captive.”

Captive, huh. Something like that...

“I already am...”

“——!”

At my words, Chiyu first looked startled.

Then she smiled, openly and happily.

That smile was pure, just like when we were kids.

“I’m happy. But if that’s true, then I’ll make you even more captive.”

A moment later, though, it changed into something indecent.

She stuck out her tongue and lightly licked at me again with slow, suggestive movements.

“Choose, So-kun. What do you want me to do?”

“...Then one more time. With your chest...”

“...You seriously like boobs too much.”

Her face stayed expressionless, but I could tell she was a little put off.

“Sorry...”

“No. It’s all my fault. Sorry for having breasts big enough to warp my childhood friend’s tastes.”

Apparently that was supposed to be a joke.

“...Yeah, this is your fault, Chiyu.”

When I laughed, she smiled too.

“Mm. I’ll take responsibility properly. I even cast a strengthening spell on you.”

About that.

“...Hey, this doesn’t feel like it’s wearing off at all. How long is it going to stay this big?”

Chiyu looked away.

“...Is there a problem with it being big?”

“You don’t know either!?”

“If you let out a lot, maybe it’ll settle down... hopefully.”

That was pure wishful thinking...!

“Come on...”

“Then should I stop?”

That question was unfair.

“...No, I’m asking you to keep going.”

“Understood.”

After that, Chiyu wrung three more out of me in a short span of time, but there was still no sign at all that Energy Up was wearing off.

“This is not something I can beat by myself. I’ll need everyone’s help.”

“Don’t say it like a powerful enemy just showed up...”

I would be lying if I said getting bigger was not enjoyable, but with my vigor still enhanced, the real problem was that even the slightest stimulation was enough to put me right back into battle mode.

“This is what a harem is for.”

“There’s no way anyone planned for something like this.”

I was sure it would wear off eventually...

But what was I supposed to do all afternoon?