I used to know a couple of twin girls in my school. I did get a bj from one and hj from the other and played with their pussies (separately). I never found out if they knew. I think they didn't talk. They were both from "proper" families, church going girls, sex talk was a no no in those families. So I think I'm the only one who knows I messed up with both of them. I kept it a secret because it made me excited thinking about it and used to masturbate to these thoughts. Besides, at the time (I was 15), I was very proud of my "achievement".