Papa datte, Shitai

Both are fairly explicit and have mild non-con elements with a later development into a cute and genuine relationship.  

It's both showing mainly a gay relationship. Dakaretai is having sex scenes too, but also a good plot. 

These are yaoi series, featuring actual sex scenes that do not get cut out in every episode. Another feature these series share, is a younger partner being a university student on a part time job. There is also the reversed dynamic, of the older partner being the "uke", and the younger partner being the "seme". Despite being hentai with sex scenes, they do revolve around a short story regarding the characters' relationships and overcoming obstacles.