Ecchi

This one is very fast paced, cracked-out humor, the main character is a sly smart charming but depraved BDSM addict and is always messing with his teacher via BDSM scenarios he sets up, partly because he knows she's into it, and partly to punish her because he's mad she's not as pure as he originally thought. Very funny but suuuuper ecchi, like this is not an ecchi subplot. This is equal parts ecchi and comedy.

Dirty but has a good plot, interesting take.
Not the average ecchi where the MC is a self insert and the girls are clingy or annoying.
Boy meets girl who is hypersexual, they get in a loving relationship. Boy puts up with girls sexual issues strangely well/comfortably/a bit too calmly.
MC is plain but not 100% cookie cutter self insert, and is a good guy (not a perv or a rapist or whatever)