A while ago I read this manga but I don’t really remember much.
I remember in the first chapter the Mc comes home and finds his roommate having sex with another guy in the hallway.
Mc asks the roommate to stop doing that cause apparently it’s something that happens often.
In the end they get together and the roommate confesses that he used to have sex so openly because he was hoping that Mc would cave in and have sex with him too or something like that.