I remember reading this but I forgot to write it down! Here's all the information I know from reading the first chapter:

Anyways it starts off with a guy doing it with a girl in a hotel, then he apologizes to her because he failed the entrance exam, and his prize if he passed would be sex. However he apologizes and she hates him for it.

He then leaves, and enters a scene with a bridge where he sees a girl in a river looking for something. Thinking she was going to commit suicide he jumps and turns out she wasn't. She asks him to help her look for her brooch/item she was looking for, she finds it.

I think afterwards he goes to an apartment to which he is going to move into and enters his room. To his surprise it's the same girl who he met at the river, except shes undressing. Also it turns out the girl doesn't know where her room is...

^ I think that's all I could remember from reading the first chapter of the manga. I wanted to read more of it but somehow it kinda slipped outta my mind.

It's not a hentai, but it's ecchi, it has the style of Yuria 100 Shiki of censoring the parts. Oh yeah, I found this somehow on Recommendations while I was scrounging around for a new series. I forgot which one though, and I tried looking for them in my "Reading List/Wish List."

Please help!

i think it may be Ki ni Naru Roomate not sure tough but if it's that, that's definitly a hentai : )

Finally! Thanks! I've been scratching my head the whole time what it was, I hate the feeling of forgetting.

I guess being able to see the acts itself even while censored is considered hentai >_<

And it's confirmed.