My ex-girlfriend fucked me while she talked to her best friend in the same room

We were living in my father's basement. I had a water bed and it was against the wall, sideways so the headboard formed a bit of a partition with the room behind it. Her best friend was with us and it had gotten late, so she stayed the night on the couch behind the headboard. She didn't bring pajamas or anything because we hadn't planned on being out so late.

She had on a body stocking under her outfit. I had never seen or heard of it... she took off her clothes and just sept in that. It covered her just as well as any outfit, well certainly as well as a one piece bathing suit, but I was hard as a rock watching her take it off. We all laid down and my fiance was jealous that I had been paying so much attention to her friend.

She started to kiss me and rub me while she and her friend were still talking. Before long, our clothes were off and we lay there naked. All her friend had to do was stand up and she would have been able to see over the headboard that were were laying naked on top of the covers, having sex. We were fucking sooo slowly (so we would not slosh the water around in the bed too much) that it drove me crazy. Of course, she was trying to show me that it was her and not her friend that I should want (apparently a few guys in their past left my fiance for her friend), but honestly, I couldn't stop thinking about her friend in that body suit the entire time.