Bokura ni Namae wo Tsukerunara
Read: Ch.8 Incest: They‘re blood-related brothers, but their parents got divorced and separated them in elementary school. Actually more fluff than I‘ve expected for this one. Seme isn‘t sleeping around, just staying with some other friends overnight to avoid uke. But he was a playboy before seeing uke with his bf and realising his feelings for his brother in middle school.
bros.
Read: Ch.5.5 Seme is a playboy with ONS, while uke has had many bad relationships just like the current bf, who‘s just a cheating abusive jerk. Seme has been in love with uke, but since they‘re brothers and thinking the other is straight, seme never made a move on uke. But now, he‘s totally devoted and tries to win uke over with push-and-pull.
Haikyu!! dj - Onedari Kinshi!
Read: Ch.1 Wth, it‘s just a nice smutty oneshot. It’s fictional, and the mangaka did a great job with this ship. Calm down, and if you don‘t like it, just don‘t read it.
Kouten Brothership
Read: Ch.2 Comedic story with age gap and incest. They‘re half-brothers.
Eri and Her Older Brother on a Certain Day