I don't really know but I've read a few of popular x unpopular school life with ml players so maybe you can see if it's any of these?
http://www.mangago.me/read-manga/kyou_koi_wo_hajimemasu/ (out of all the ones I'm giving this is probably most likely what you're talking about cause it does have light sex scenes unlike the other ones)
http://www.mangago.me/read-manga/l_dk/
http://www.mangago.me/read-manga/kyou_no_kira_kun/
I have read all of them, the one also was in the same taste but it was short, just a few chapters. Most likely it was an unpopular manga.
Anyway, thanks for the answer <3
Guys I am looking for a Japanese manga which I read 5 6 years ago. It was about a popular high school boy who sleeps around a lot and a normal girl. I guess it contained light sex scenes too. Also, there were some scenes about the rooftop, him giving her his jacket (or opposite) and she was thinking that he wasn't her first but he is different or something. It is all I remember. It keeps ticking me and I could not figure out the name. If someone can help me to find it, would be grateful （/TДT)/