Fucking [M] sisters hot [F]riend

First post and first time sharing this story with anyone else but the girl I fucked. Sorry for the length, hopefully the back story isn’t too painful, I marked where the good parts start.

I moved to a new city for grad school when I was in my early 20’s, I was accepted to a major university (my long shot) and I was over the moon. This also coincided with the ending of a 6 year relationship and a subsequent depressive weight gain which negated any esteem I felt from professional accomplishments. Thankfully for me, my sister was fairly popular and not too much younger than me, so hanging out with her/her friends was a god send.

As time went on, I think I had a bit of a mental break, and became known as being kind of a wild card, very good at drinking games, fun at parties and quickly made a lot of great friends.