Zenbu Shinka-chan no Sei

"You have a big penis, don't you?" In the classroom after school, holding my hand, Shinka, the most innocent and beautiful girl in school, started talking to me!
I, Touta, who has become the subject of evolutionary psychology research, have been going out with Shinka since the first day we talked!

This is a coming-of-age romantic comedy with a beautiful and innocent JK girl who is very interested in "human sexuality"!