The uke gets raped by an old man, and at school the bullies find out. It’s kind of implied that the main bully likes him but the uke finds the old man again because he actually likes it. Also that old man was said to be the (what’s that word for the character that plays a role) to get couples together. There’s an example.
https://e-hentai.org/g/1008856/32b5aac845/
Mobu Oji-san Demo Koi ga Shitai!