Untitled story idea

There's a girl who has a friend she talks to online about sex, but she never thought they would meet up so she lied about having a boyfriend and would tell the friend about the sex they were having (which was basically just her fantasies). But one day the friend says she and her boyfriend are going to be in the area and wants to meet up, so the girl asks her brother to pretend to be her boyfriend. He's not crazy about it but grudgingly goes along with it anyway. So they meet up and it goes fine, the friend doesn't suspect he's not actually her BF. But they end up going to the friend's hotel room, and the friend drops on them that a while back they talked about how it would be hot if they had sex with their boyfriends in the same room and asks if they're down and internally they're both like shiiiiiit but neither one of them can bring themselves to break character so they go along with it and end up liking fucking each other.