This is something I never expected to happen. My wife and I have been married for over 25 years and we were each other's first. My wife was raised in a fairly conservative family (or so I thought) and our sex life was good. A few years ago I started introducing stories to our lovemaking and it almost always resulted in a mutual happy ending. I had to keep the stories fairly tame because she said she did not want to even think about sex with another partner. I never really believed this because she would always have an orgasm if I told her a story about someone else kissing her breasts or rubbing her vagina. Nonetheless she would not let me tell her someone else was going to penetrate her.
I have always thought my wife was a beautiful woman in a Jan Brady sort of way. She is quite tall with a dynamite body. She sports a set of c-cups with great nipples that are very sensitive. Last summer we experimented with shaving and now she keeps a tightly cropped landing zone which I love to kiss and touch.
Anyway onto the story, which is why, you are here. We were at a family reunion with my wife's family and there was a mix up with the rooms. Our 4 kids were booked into a room with my wife's brothers 4 kids and we were booked to share a room with her brother and his wife. The wives decided to let the kids have a big sleep over and all share a room while the adults would just share the other room. I figured that would put an end to any sex I had hopped for because the women would be too shy in a shared room and they would be constantly checking on the kids.
Around 11PM we finally got all of the kids tucked in and to sleep so the two couples decided to head to bed to be rested and fresh for the next days activities. My brother in law is quite a few years younger than I am and for whatever reason I still think of him as the 12 year old he was in our wedding. He married his high school sweetheart. She is a tiny women about 5'2" with nice b cups and a very trim body. Her high school prom picture was quite attractive with very prominent headlights. Even my wife's grandfather commented on them. Well as we changed into our bedclothes it became clear both couples had planned on a little fun and had only packed the skimpiest of sleepwear. We all had a little chuckle about it but since we were all family the women wore what they had. I could not help but stare at my sister-in-law. Ever since her high school picture I had always wanted to see more and there was very little left to the imagination. I was a little surprised when I noticed my brother in law checking out his sister, my wife. I figured why not, a good-looking woman almost nude is still a good-looking woman almost nude even if it is your sister.
Well after the lights were out and good nights were said my hands got a little curious and I started rubbing my wife's back. I could tell she was enjoying my touches so I got more daring and slid my hands around to her breasts. I found her sensitive nipples quite hard and erect. As I started to caress her boobs and tease her nipples her hand found its way to my cock. I think the idea of being so close to another couple, let alone it being her brother and his wife, had me extremely hard. My wife whispered to me how much she loved it when my cock was so big and hard. Well one thing led to another and my wife got on top of me and slid my cock inside of her. As the head of my cock passed through her opening she let out a little sigh. It was hard for me to keep quiet because she was so wet and slippery it felt as great as it ever had. I worried a little about the noise and so I looked over and saw the covers moving in her brother's bed and figured they were up to the same thing.
I whispered to my wife to look at the other bed and she saw the same thing I saw which turned her on so much she let out a loud moan. I think this was the sign that it was ok because the other bed got a fair bit noisier and I could see the shape of my sister in law sitting on top of her husband. It almost seemed like a little competition between the couples and the movements got bolder and the sounds louder. Unfortunately it did not last long as both couples quickly climaxed. The room had a strong smell of sex and the breathing was quite fast from both beds. As my wife released my cock it slid out of her and made quite a slop sound. My wife gave me a great tongue kiss and said goodnight. Goodnight, it sure was. I had never thought my shy wife would do anything like this let alone adding the kink factor that it was her brother in the next bed.
My wife quickly drifted off to sleep but the scent of sex in the air and what had just happened kept me awake. In fact the more I thought about it the more aroused I was getting. I got up to go to the bathroom and I thought I could see that my brother-in-law and his wife were still awake. I was a little worried because I was still semi-hard and I did not want to be showing too much. After I finished I left the light on in the bathroom and closed the door so the room would not be so dark.