Trying to find a manga

[BlackJacketn]

Can't remember the name but it's kind of like You Were Experienced, I was Not: Our Dating Story, but the girl is freely "sexually active" and the main characters just start off as friends and go from there. I remember first chapter the MC guy walks in on her and a dude getting it on at his desk (I think) but he just brushes it off as he grabs his book from his desk. She tries to seduce him later but he shuts her down saying she's not proper and pure with black hair like he prefers. She later tries to play to his preferences and you find out when the same guy finds her and tries to continue what was interrupted that she's just trying to be liked and that's how she ended up in her situation.

 

[undeed]

dangit, I know this one,
but since the story is so typical run-of-the-mill routine, it led me to a wild goose chase twice

Nanjou