The Ninja Academy also helps the Game Playas master their endurance. With a long line of game girls waiting to get laid, they're gonna need it.

Come to think of it... I don't think I ever explained how the Playas can go the distance with so many women in a single outing. I just kinda chocked it up to 'this is a hentai manga, that's how it works' because if you notice, a LOT of hentai manga has the guy, girl or both go round after round after round like it was nothing.

Now we can say that Mai and her little dojo of lust is what helped train the guys into going all night.