lets see school life boy falls in love with teacher definitely ecchi cant remember much about it but there was fighting. and a certain scene still sticks with me.

The boy's childhood friend is getting bullied by other girls and at a point makes here take her skirt off. Then the dude shows up and starts beating up the girl and shit.

sorry i cant detail it anymore this is all i could remember about the manga.

Unbalance X Unbalance, its a manwha

Yeah, it probably is Unbalance x Unbalance, but I don't think the girl is the guys childhood friend.