I'm looking for a doujin where this student is at his teacher's house, I'm pretty sure it's Christmas. She's giving him some tutoring, and he's trying to stay there because he's clearly being abused at home - I think the teacher notices a bruise on his cheek? They end up doing it, and it's surprisingly nice and comfy. As far as the sex, it's pretty vanilla.
Shin bump
Bump4interest