A little hottie that my friend occasionally fucks heard how big my dick was and told him that she wanted us both to fuck her sometime; she said that she never did two guys at the same time, but thought it would be awesome. So a few weeks ago we were all out drinking and ended up at my place long story short; the fulfilling of her fantasy fuckfest occurred, and lasted for nearly two intense sweaty hours I still question that she never did that before. BUT When she was on top of me (facing me) I was in her ass; my buddy came over and pushed her down and stuck his dick in her ass with mine! She let out a scream but kept going (?), however, it completely ruined the experience for me (the dick, not the scream). Ive had other threesomes with a dude and all was well. Problem is, she wants to do it again and I have zero interest in fucking her with my buddy. I told my buddy and he thinks Im crazy. Am I being a prude or is this crossing the line of threeway etiquette, if there is such a thing?