My wife and I went to visit her parents. On Saturday afternoon, I felt sleepy and went to nap in my wife's younger sister's bed. I awoke to find my wife in bed with me. We started doing it spoon style because the bed was small. We were getting right along when my sister-in-law, then about nineteen, came into the room. I just kept on pumping slowly. I think she knew what I was doing, but she didn't say anything. I had a huge orgasm knowing that she was watching.