So, I (17m) and my twin sister (17f) have always been close friends. We would always party and talk about life with each other. To get to the story, we were at a party together (you know a typical high school party for cool and hot people) when somebody suggested that we partake in seven minutes in heaven anonymously. Two people walk in the closet and I see that my sister is next, I lounge to position in a moment of horniness and disgust to walk in together with my sister, she is unknowingly doing something that will probably haunt her for the rest of her life. We engage in the best sex I have ever had (and I am the type of guy who gets to fuck a lot). We go out into the light, and the look of pure terror she gives me before she starts to cry hurts. Reddit, am I the asshole for enjoying having sex with my sister? I'm so confused, and she won't talk to me.