It was this story where it starts with a girl catches her currently single roommate masturbating. Eventually it leads to watching him jack off, to both doing it together, then in going out together, then in the same bed, doing each other then eventually sex at the end.
Some other details I remember is that the girl was currently in an dispassionate relationship with a guy that drank beer all day, leading to the main drama in the story, and that the story was mainly told from the guys perspective, except for a few perspective shifts.
Source: reddit.com/r/sexystories/comments/jqrj4x/assuming_you_can_ask_for_help_to_find_here