What's this based off of!?

There's several manga/anime I remember from the 90s & 80s that involve a girl going to an all-boys school or similar mostly male area while having to conceal their true gender but this doesn't look familiar at all.

I'd really like to see more of this even if there's no basis.

Base +6, bahamut9191 -11

This is the eighth in a gender bender series the girl pretending to be a guy was a guy who was being mean to the mormal girl next to him and was punished by Kami sama being turned into a girl himself

Base +4