I am trying to find a manga about a transfer student. He is trying to live a normal high school/college life but he actually was a former delinquent. He is trying to keep people from finding out but he keeps accidentally almost responding like his old self would have. I think he's the main character, but he might be a side character or it could be part of a manga that has multiple stories/couples.
The manga has a father and son who are both gay (no incest) but I don't think out to each other originally, but I think the son resents his father. The father has an unrequited love for his best friend. The son has a crush on his own best friend and I think they date briefly. I remember there being lots of drama and yelling. Somehow the dad ends up dating the son's friend/boyfriend. I can't remember if the other two get together. I think they do?
This time it's that Yukinori is probably allergic to citrus. I'll probably never get tired of reading this one.