Me and my wife were over at her sisters place. We were having drinks and I had a little too much. It was late and her sister suggested we just stay the night. My wife and her sister stripped me down to my underwear and threw me into bed. I was drunk but still sort of aware of what was going on. Her sister did ask my wife about my underwear coming off but my wife told her she wasn't going to allow her to see that much of her husband. My wife said she needed to use the washroom and left the room. With my wife out of the room and my sister still there I felt her pull down my underwear. She was looking at my cock and mumbling to herself about what my wife had said about "not seeing that much of her husband". She was now mumbling about seeing all of her husband. I do remember her hands touching me and when I heard a toilet flush is when my underwear quickly got pulled back up. My wife returned and asked how I was. Her sister said I was just sleeping and made mention that I would probably be more comfortable if my underwear came off. My wife told her if they were going to come off it would be when she wasn't around as she wasn't going to have her see me like that. She left the room and we went to sleep.

During the night I needed to use the bathroom and went down the hall in just my underwear. After I was done I opened the bathroom door to see her standing there in a robe. However, the robe was untied and slightly opened exposing her pussy and part of her breasts. She pushed me back into the bathroom and closed the door. She sat up on the bathroom counter which caused her robe to open fully exposing her breasts and with her legs spread exposing her pussy fully. She told me to come closer and pulled my underwear down. She grabbed my cock and began to stroke it until it was hard. She then told me to fuck here. I did as she asked and there we were in the bathroom fucking as my wife slept in a room down the hall. Once done we quickly cleaned up and went back to bed.

In the morning my wife began telling me how her sister wanted my underwear off last night but she told her they were staying on. My wife told me that me being naked was only for her to see and not her sisters. She then went on to say her sister is family but she also is a slut and didn't want me to become one of her hundreds of guys. She said it was unlikely it would happen, but also mentioned she just didn't want her sister seeing me naked.

I didn't say anything and hoped her sister wouldn't about our bathroom meeting last night.