My wife's GF was visitng us. We had all gone to High school together and known each other for 40 years. During that time we have shared rooms on vacations, so being nude around each other was no real big thing. I got in the hot tub on our deck one night and she decided to join me with her glass of wine. My wife doesn't like hot tubs ,so she sat out and chatted with us. Agin no big deal since we were facing each other in the tub. Wife went into the house for some more wine and to use the bathroom. Our friend got up turned around and sat on my lap and told me she had always wanted me in her. I got very hard,very fast and did it. and went off like a teenager doing it for the first time. Wife called ou the window and aasked if I wanted anything else to drink as she was coming back out. I could barely talk and said ,Not thanks". we turnd to face eachother again and picked up cahtting were we had left off with the 3 of us. It was the most bizzare sex I think I ever had. Wife has no clue to this day.