Fucking his sister-in-law is the best thing that has ever happened to him
He always thought that brotherhood and those things they say on television would help when the time came, but like anything the media wants to sell, it was a lie. Because this kid, right now, is discovering that fucking his sister-in-law is the best thing that has ever happened to him in his life. And basically now he wants to always be penetrating her pussy. After she gives him a blowjob and he can see that she does it excellently, and after she spreads her legs and he can feel the heat of her slit, there is no turning back. He has to keep doing it.