We hosted a party last night. My wife is a tease and a very attractive woman for her age. Toward the end of the night after most everyone had left, as a bit of a joke she sat on this young black guy's lap and they started kissing rather passionately. It was a real turn-on for me to watch them, especially when he began feeling her breast. I decided to give them some time and see what developed so I went out to the kitchen and poured myself a drink. When I returned a few minutes later she was straddling him and they were enjoying a very hot dry fuck. Her blouse was undone and her breasts were exposed as she bounced up and down on his lap. I walked back into the room and said they should go upstairs and do it. I watched as the young stud fucked my wife with much vigour and she responded with cries and moans I hadn't heard in a long time. I couldn't contain myself and jacked off while he filled her married pussy with his big cock. A great end to a fun evening.