That cover page is just great...Imagine seeing something like that hidden under the blanket of a naked woman.
Still, I suppose when a girl asks you to show her your dick, it'd be rude to say no, right?
"Yes. Why ARE you the only one who did well?"
"Well, it may have something to do with the fact that I knew it already, and you two were fucking me like jack rabbits."
"Oh, ehh... Right."
Good old hentai learning session with the classic time table: first we studie math,then you show us your dick and at the end we all have sex (and lose our virginities).