Harenchi Gakuen is titular elementary school whose teachers and students are all perverts. Boys peep girls changing. Girls pull up their skirts and show off their panties. Actually, it’s not as evil as you imagine. They’re like cubs playing together. It’s only pre-school eroticism, nothing sexual.
The protagonist of the misadventures are Yasohachi “Oyabun (Boss)“ Yamagishi and Mitsuko “Jubei“ Yagyu.
Note: The PTA attacked the comic’s immorality and the manga ended up being cancelled.