( This is the Asahina Mikuru from the even further future and time plane talking BTW..)
"Oh, you still don't believe me?"
Asahina in a secretary-like outfit said naughtily,
"Then I'll show you proof!"
She then promptly began to unbutton her blouse. When she opened the second button, she revealed her bust to my astonishment.
"Look, can you see the star-shaped birthmark? It's not stuck on! You want to touch it?"
There was a star-shaped birthmark on her left breast, an attractive highlight on the white skin, radiating charm.
"So now you believe?"
How should I say this? I don't even remember ever seeing whether Asahina had a birthmark on her breast. Though I was kinda forced into seeing her change when she dressed as a bunny girl a while ago, I wouldn't be so focused as to notice such a small area. While I was thinking the above, the attractive, mature-looking Asahina said,
"That's strange. If you hadn't told me that I had this birthmark, I wouldn't have noticed it myself."
Asahina confusedly shook her head, and then, as if realizing something, her eyes widened and she blushed furiously.
"Eh......Oh no, I just......T...that's right! We still haven't......What should I do?"
(This kinda implies that they are going to do it in the future. So if Mikuru is his sister then