Somehow without my realizing, the girl I liked for all those years had become a man-eating sexpot.

Summer vacation.

Ordinary protagonist Youta (virgin) found himself making out with his childhood friend Rio (non-vigin)...

"Do you like doing it with me...? I'll take it off for you..."

Youta was bewildered. It was his first time, but certainly not hers. He put himself in her capable hands.