Also Modern MurderMedia anon (M³?)

CW incest and forced breeding / cnc
Alternate route of the AU where Alastor's a transman and his mom didn't pass, but instead divorced his dad for cheating. His dad immediately marries the woman he was cheating with and has a son with her(Vincent) while having visitation rights. Everything else falls along the same route, but after a few years of secretly dating, Vincent gets the sudden fear Alastor will leave him. So being his father's son and also rather awful, one night he purposely makes a tear in the condom so it breaks and he can knock Alastor up in hopes to keep him forever. He's aware of the risks and consequences, but also is incredibly turned on by breeding his older brother.

Alastor is shocked at first, and Vincent expects to be yelled at, but instead is told "Took you long enough" and "Since you've already cum inside me, let's make sure it takes"