I'm a little shy (I've had a few drinks about now so that loosens me up) but the only time I've really been turned on when watching others have sex was with an ex gf of mine. We were into watching porn together and I happened to rent some interracial stuff. She got way too into watching this well hung black guy bang this white girl. She was hotter and wetter then I had ever seen her! So I rented some more interracial stuff and she had the same reaction, she began wanting to have fantasies that I was this well hung black dude banging the shit out her during our sex. So I thought I would test out her willingness to bang a black dude. I've got this well hung black friend from college that I played baseball with to come over and have drinks with us (Mike is a real 10 X 7). We started to get a little drunk and I left the room to let Mike start flirting with my gf (all a setup by the way). The next thing you know she starts sucking him off right in the living room on our couch. He calls a timeout and comes to the kitchen, where I was watching from and asks me if he could bang her! I said fuck it, go ahead. My gf and I were not that serious and I had never seen my gf fucked by a bigger dick than me and thought maybe I'll get into it.
It took Mike 20 minutes just to get the head in her. But once he patiently worked his way in, she was squealing like I had never seen her! Screaming to slam his big black dick into her and she took it all! I stood there in the kitchen, watching from the bar and masturbated myself to a great solo orgasm! The episode took a heavy toll on the relationship of my friend and I, in fact we no longer even speak out of embarrassment I guess. And the gf is long gone to pursue other fantasies I guess. I haven't watched another couple have sex in person since, except in pornos.