Upon looking up at the sky, the stars were already s.h.i.+ning.
It was still the first day since we arrived at Rein"s southern country home. Even so, I had quite the experience.

We had s.e.x on the tropics sh.o.r.e, s.e.x inside of the forest, and s.e.x while the animals were watching.

I thought that reading books at home was the most restful and significant use of time.
However, returning to the wild in the midst of the forest like this was surprisingly fun. The expression of returning is a bit weird, though.

“However, I"d hate to do this everyday.”
“……?”

Right now, I was immersing myself in the onsen that was prepared in Rein"s house. Entrusting my back against the edge, I warmed myself up.
Since it was after a thorough bout of s.e.xual intercourse, I wanted to wash my body.
This hot spring was also splendid, having a moderate size on top of a good view as well.

“The starry sky is especially good, huh?”
“So many!”

Rein was still in her childhood state even now. Riding on my lap while completely naked, we bathed together.
Because this girl has memories regarding me, I thought she wouldn"t become so attached to me, but it appears that wasn"t the case.
Since children are only interested in themselves, she might think of me as a convenient vibrator or something.

“Even though she"s a child, having a vibrator is such an anomaly, huh?”
“……?”

Every time I murmured, Rein shook her head side to side as though to try and look this way. Since she didn"t move from atop my lap, she naturally wasn"t able to take a peek at my expression.
Finding such a young Rein adorable, I poked her cheek.

“……nngh.”

Upon stopping her movements once her cheek had been caught, Rein began to suck on my poking finger.
While making a slurping sound with her drool, she beamed with a grin.
It should be fine now.

“[Defeat is Yours].”

Quoting the keywords, I had Rein fall into a trance while still sucking on my finger.

“Rein, from here on, you will be able to see a stairway in the depths of your heart. Yes, it is the stairway that you just climbed down today. Please climb it.”
“……stair, way……climb.”
“That stairway will make you into an adult again. Look, as you climb step by stpe, your body will grow.”

In this situation, I"m planning to release Rein from her regressed state.
Furthermore, I will just release her from her regressed state, making it so she retains all of her memories of that time.
I don"t know what kind of triggers there are that could cause a mental illnesses of regression for humans. If she retains her recognition of that time, then, well, even if she had doubts, she probably wouldn"t pursue it.
After that, all I have to do is match my story with her. If she tolerates the fact that she regressed and we talk about all of the contact we"ve made with each other, then I"ll be able to flexibly deal with it.

“Well then, awaken……now!”
“……fueh?”

Rein woke up. While my finger was still in her mouth.
As expected, she was stuck in a daze for the first few seconds, apparently unable to follow the situation.
However, after another few seconds, her eyes regained a gleaming s.h.i.+ne that was much like her.

“Guoh!! Boh!!”
“Peh!”

Rein suddenly elbowed me in the sides. After that, she spat out my finger and took distance from me in a single bound.
Receiving pain in my side, I writhed in agony inside the bath. It shouldn"t have hurt that much, though, since I made it so that this girl wouldn"t be able to induce harm to me.

“b.a.s.t.a.r.d……my weak, point-“
“Don"t come closer!”

It would seem that my weakpoint had been noticed. Kokoro also tickled my sides a lot, so I already knew about it.
Rein was like a cat who had their territory raided, exposing her wariness as she slowly but steadily took her distance from me.

“So you"ve……returned to normal?”
“…………”

I deliberately implied that I was aware of this irregular event.
Like this, I emphasised the fact that Rein had regressed.

In doing so, I wonder what happens next?
Perhaps because Rein remembered what happened and couldn"t bear the embarra.s.sment, she soaked herself in the hot spring up until her forehead as she blew bubbles in the water. Even if she did such, her face being red was completely visible.
For the time being, I"ll follow up like a person with empathy.

“What, Rein had a strange heat to begin with, so don"t worry so much about it. Even I"ve gained some counselling knowledge from Kokoro, after all.”
“……blub blub.”

While still diving in the hot spring, Rein slowly approached me.
And then, after raising a splash, she rose from the water"s surface and grabbed my chin.

“Forget it. Seriously.”
“Haha……haha!!”

I couldn"t stop laughing.
The area between her brows wrinkled as Rein gritted her teeth and glared at me. It was an incredibly vexed and wonderful expression.

“……you-“
“That Rein was also cute. Even if you don"t mind it so much, I"m happy that I saw that Rein.”

For the time being, since it"d be dangerous to worsen her mood any more than this, I"ll praise her a bit.
Of course, because I couldn"t do anything as skillful as currying favour, I just spoke the truth.

“It"d be a waste if I forgot it, right?”

These were words from my heart. The intercourse was also fun, after all.
Rein continued to fixedly meet my eyes as though appriasing me, but eventually gave up, letting go of her hand after sighing.

“That"s right, you were that sort of guy.”
“It seems like you finally get it, huh.”
“I already knew. Right now, I finally gave up.”

Pressing the back of her hand against her forehead, Rein rose as though to swim on the hot spring"s surface.

“I also know the embarra.s.sment of having your own childhood self being seen.”
“So what? There"s no way we can even things out.”
“Then, when we get back, do you want to see picture of me when I was a child?”
“…..I"ll refrain, thanks.”
“Then this will be a secret between only the two of us.”

As soon as I said this, the conversation stopped.
Certainly, the result wouldn"t change even if we disputed it over more than this. Rein also stopped.
Like that, without us particularly conversing with the other, only the sound of the slos.h.i.+ng hot spring water persisted.

However, neither of us got out of the bath as time pa.s.sed while we were both together.

“……really, how stupid. I want to disappear.”
“……Rein?”

The first one to break the silence was Rein. Her eyes were gla.s.sy, and it looked like she had given herself up to despair.
While immersing myself in the water up until my shoulders, for the time being I waited for her next word.

“Even though this sort of thing has never happened up until now, my body has become strange, and my mind even turned into that of a child"s. I really have no idea what"s going on.”

That was Rein"s whimpers.
Certainly, it"s abnormal that she"d suddenly become h.o.r.n.y or regress into an infant. In the face of this bodily change that has continued ever since the start of this year, it wasn"t impossible for Rein, who was still a girl, to be bewildered.
Those who don"t have to worry about this kind of situation is probably only me as I was the cause that created it.
However, how unexpected.

I was considering whether or not to increase the mentally strong Rein"s physical ability.
However, upon actually coming into contact with Rein, she turned out to not be such a strong woman. She gets shaken, and she"s also sensitive to other people"s facial expressions. She"s a normal girl.
It"s just that, from everything that"s happened up until now, I am convinced that it something psychological is the cause.
It seems that I still have to continue researching more.

“You, why don"t you think it"s strange? I don"t mind if you call me weird, so-“
“It"s not like I have to understand everything about someone, see.”

I will also continue my hypnosis from now on and make new discoveries. That makes me a little happy.

“I think that it is hyman to expend effort into trying to understand it. That"s why, even if there"s something I don"t understand, well, even if I think it may be strange, I can"t really hate it.”
“……”
“Besides, I like the Rein that I know right now enough, after all. The rest of the playfullness that I didn"t know about is cute, so isn"t it fine?”

I got carried away and my mouth slipped.
Thinking normally, this was the way of speaking that made it seem like I treated her like a toy. Since I"m actually using her like a toy, I can"t really make any excuses, though.

I don"t know what Rein thought, but she once again immersed herself in the water up until about her nose, blowing bubbles in the water while looking this way.
In that state, she walked on all fours with both hands and both feet until she reached my side.

“I don"t really get what you"re saying, though.”
“I-I see, my bad for saying something strange.”

When Rein quietly plopped herself beside me while grasping her knees, she appeared to have become quite docile-looking.
I guess it felt like she had been released from her absurdly strange despair?

“However, as far as I know right now, I also understand you.”
“Understand what?”
“If it"s you, then whatever happens, you"d talk about that sort of thing.”
“Hm? I don"t really get it.”

Rein turned towards me and slowy extended her arms.
And then, after tracing my neck with her fingers, she picked at me with her thumb.

“If I were to strangled this neck, then I wonder if your expression would change as expected?”
“Who knows, first of all it"ll be a problem if that happens here, right?”

What in the world does Rein want from me?
Certainly, on top of choosing Rein, I had, for the most part, accepted her changes. Since people who don"t change are boring, I thought of it more as an honour.

“Say, whether its yourself or someone else, I think that people suddenly changing is scary. I also had friends when I was a child, you see.”
“Haha, don"t you also have them now?”
“But don"t you wish for something that doesn"t change?”

Mai, and I guess Sunou and Kokoro are also in that category.
With her hand still placed on my neck, Rein brought her face closer. Meeting her eyes at a distance where not even a single cigarette could be put between us, she held onto me.
In the face of such a Rein"s a.s.sault, I conversely ended up becoming calm.
The changes were only something superficial. Her true nature was firmly rooted somewhere. She thinks that it"s scary because she couldn"t see through that.

In order to conceal her fear, the current Rein had become like a girl trying to put up a front.
To her, the thing that doesn"t change is the other people that know of that.

“Say, not gonna do it?”
“Not gonna do what?”

Grabbing my wrist, Rein pushed it against her left breast.
The sensation of the soft breast being squeezed and Rein"s heartbeat was firmly transmitted to my hand.
I see, so she"s become h.o.r.n.y, huh?
As usual, she doesn"t know when or how it was activated.

“Nn……”

Rein wrapped her arm around my back, and put her lips over mine while I was in a state where I was unable to escape.
Sandwiched between Rein and the hot spring"s edge, I could only remained pa.s.sive.
When both of our lips seperated, elation surfaced on Rein"s cheeks, although only slightly.

“Are you getting carried away?”
“I might be.”

Rein laughed back at my words. It was a rare smile without sarcasm. She really is getting excited.

“Show your appreciation to the kind me.”
“Hyah!”

Upon standing up, I held Rein up and lifted her out of the water.
Rein"s body really is light. To the point where one would wonder where did such strength come from in these slender arms.

“Hold on tightly.”
“……”

Rein nodded, wrapped her arm around my neck and clinging to me.
Both of our chests. .h.i.t against each other, and an exceedingly soft sensation reached me. The beating of her heart could be heard from both sides, as though they were linked.
Using my free hand to hold Rein"s b.u.t.t, I rubbed my p.e.n.i.s against her crotch.

I played too much in the day time that I didn"t particularly feel like making any sort of elaborate scheme.

“I"m gonna put it in.”
“Is there a need to confirm it with me?”
“Nope. Don"t you understand it well?”

Although I could see neither the p.e.n.i.s or v.a.g.i.n.a, my body remembered generally where they were.
Thanks to Rein firmly keeping balence with her clinging arm, I was able to lightly adjust the position of Rein"s b.u.t.t.
While unable to see, my p.e.n.i.s felt an entrance-like sensation, entering inside the hole just like that with a splurt.

“Nngh, aah……!!”

Apparently I hadn"t made a mistake.
She was properly wet, and insertion was smooth, but Rein"s heat was awfully weak.
Well, not that it matters.

“……aaah!!”

I diagonally moved my waist back and forth, thrusting up into Rein that was still being raised up.
There"s a sense of security that comes from this girl clinging firmly onto me no matter how many times we do it.
That"s why I used Rein"s weight to thrust up as though to pry into the depths of her v.a.g.i.n.a—or rather, even further.

“Nngh, nnnngh!! Kyaah!! ……as always, sorry.”

What is she saying sorry for?
No, I guess she"s saying sorry for always being f.u.c.ked by me, huh?
That might be why, at the start of intercourse, Rein proactively came attacking at me.

From my perspective, that sort of thing was just needless anxiety.
The undulation that Rein"s v.a.g.i.n.a naturally possessed firmly settled as though giving the illusion that the body was supported only by the p.e.n.i.s and v.a.g.i.n.a.
The interior of Rein"s v.a.g.i.n.a"s flesh undulated as though it were a different creature, continuing to a.s.sault my p.e.n.i.s in a Rein-like manner. Even if I took the initiative, I couldn"t compete with her in terms of bodily characteristics.
My p.e.n.i.s was constantly being toyed with, as though it was being squeezed dry by Rein"s greedy v.a.g.i.n.a.

“Aah!!”

Without understanding her own abilities, Rein simply panted.
Or rather, it might be because her v.a.g.i.n.a had this that the person herself wasn"t able to endure the pleasure.

“Well, since it"s my fault that you"ve become like this, you don"t have to worry about it so much.”
“AaAah……hyaaaahh!! Aah……”

In my field of view, I could already see a lot and a lot of Rein"s face.
Perhaps embarra.s.sed to have such an appearance seen by me, or perhaps because she was humiliated, Rein bit her lip while vexedly shedding tears.

“Kyaah!!”

However, upon thrusting my waist forward, she ended up succ.u.mbing to me as a female.
How pleasant.

“H-Hey.”
“Hm, what"s up?”
“T-The end is–!!”

Rein somewhat forcibly pestered me for a kiss.
Since I didn"t need to deny her, I closed in on Rein"s face just like that.
After that, I increased the speed of my pistons more than ever, rubbing the insides of Rein"s v.a.g.i.n.a.

“Nngh…………nnmmmmmmmmmmggghhh!!!”

While in a state where our mouths, chests, and genitals were connected, we both reached climax at the same time as though our feelings were linked with each other.
Rein"s scream was buried in my mouth. Our saliva and tongues mixed together, lost in the vulgar squelching sounds.
My p.e.n.i.s e.j.a.c.u.l.a.t.ed, the s.e.m.e.n so dense that it would make the hot spring muddy enetering inside of Rein"s v.a.g.i.n.a and flowing into her womb.

While the both of us stayed still in that state, time pa.s.sed by as though that moment had been stopped.

“Puhah!!”

After a while had pa.s.sed, I suitably seperated my mouth and finished up.
Releasing Rein like that, and she went inside of the hot water. The impurities would mingle in with the hot springs, but, well, it should be fine since the only other person using this place besides us would be Rein"s grandfather.

“Haah……hyah……”
“Tsu……”

I felt a p.r.i.c.kling pain around my back. Apparently, because of Rein"s desperate clinging, it might have a bruise on it.
Rein arched backwards as she was, her body floating on the surface of the water as she looked up to the sky.

“Say, this starry sky, right now someone"s looking at it, right?”
“Who knows?”

Rein was still out of breath and her chest was heaving up and down. Even so, she happily continued to talk so as to not lose the lingering memory of the event.

“If we"re the only ones who are seeing these stars, then right now I think it"s fine.”

Rein is in a good mood. Even though there was no reason for it, she was smiling.

“If such a thing happens. Then humanity wouldn"t exist in this world, right?”
“You and I are here, aren"t we?”

Wouldn"t that in itself be the downfall of humanity?
I don"t think I can bring myself to part with civilisation and other literature.

“Don"t make it so that the human race will go extinct if we don"t make 100 children.”
“Hahah, that might be a bit tiring.”

No, that"s impossible.
Whether Rein was still getting carried away or not, she smiled even at such a ridiculous joke.
However, such an innocent smile shone on the surface of the water, looking like a very valuable thing.