I remember the first time... In my senior year of college, Al and I had been sharing an off-campus apartment as well as Angie. Our agreement was that if the other was home, sex was to be in our individual bedroom. Angie was to be fully clothed (at least in a robe) outside of a bedroom. One night, a class was canceled because of the professor being sick. Not having anything else to do, I went back to the apartment. When I opened the door, Angie was "cowgirl" on Al with his hands on her breasts as their tounges danced while they kissed. I could see the root of Al's cock where it went into Angie. I said, "Sorry. Class canceled" and went on into my bedroom. Both Angie and Al later apologized for the surprise. As did I. It didn't change things much. Except Angie was a little freer in her nudity in the apartment. But, sex was still for the bedroom. either Al's or mine.
And, yes, it did turn me on to see Angie being fucked like that. When she apologized later, Al's cum was leaking down her left thigh...
-Rick.