I woke up to a strange sensation in my body.
Ah… Nao. Nao was on top of me.
I didn’t know why, but there she was, sitting on me while I was asleep.
That wasn’t all.
My crotch felt like it was wrapped in something—something warm and pleasant, enveloping me entirely.
What the hell was going on?

"Ah… What are you doing… Ahh…"

"What do you mean… Ahhh… You know, don’t you, big bro? Haaah… Ugh…
Sex… feels this good… Ahhh… Hey, big bro… Are you close?
When guys have sex, they release sperm, right? It feels so amazing… Ahhh…
The first time can be tough, right?
I think I’m about to… I’m gonna cum… Ughhh…"

"Eh? Sis, what are you doing? Ahhh!
Sis, with your own brother?.. Why? You said you’d help me!"

"Ah, well… This is just a little test… you know?"

"A test for what?!"

"Well, I thought maybe Makoto might find big bro too big, so I was checking for her.
I’m the experienced one, after all. I think it might be too much for Makoto, though. If she’s okay with it hurting…"

"Yeah…"

"So, big bro, that’s how it is.
Makoto wants to do it with you. Go on, Makoto, tell him."

"Ah, yeah… Big bro, I like you. So I want to have sex with you."

What the hell are you two even saying?

[Translated from dlsite]