The thought of this still makes me horny.
I am married to a wonderful woman; however, her older sister, Linda, has always made me horny.
One time, my wife, my sister-in-law and I decided to meet in St. Louis for a weekend of sightseeing and visiting cultural events. At that point in time, my sister-in-law and her husband were going through some financial hard times so, in order to save them money, we decided that we could share a hotel room.
The weekend started with no unusual dynamics or hidden agenda's. However, I have always had a hard time keeping from staring at her really nice ass and this weekend was no different. Her great tush drives me nuts! On Friday evening, after a full day of sightseeing, we called it an evening. Linda turned on the television and laid on the hotel floor to watch tv wearing only a t-shirt and nice white cotton panties. She didn't seem to mind me seeing her undies and the nice ass that they were concealing. Needless to say, I was mesmerized and aroused.
We had a room with two beds. She, of course, occupied one and my wife and I the other. After we went to bed, I woke up at about 1:00am, needing to go to the bathroom. As I passed the closet, I noticed those panties on the floor of the closet! I managed to 'borrow' them and took them to the bathroom with me. I masturbated by rubbing them against my hard cock and came in the crotch of her panties. When I returned them, I wondered if Linda had actually noticed me because she was stirring as I returned to my bed.
The next morning, the three of us woke up about the same time. I thought I'd take my shower first in order to allow my wife and Linda to take their time. However, when Linda noticed I was going to shower, she popped out of bed and said, 'Jack, would you mind if I took my shower first?' Although this was quite sudden, of course, I relented, not understanding but okay with it.
Linda showered and came out about twenty minutes later and announced, 'it's all yours'. I proceeded to the shower and noticed a pair of her panties on the floor of the bathroom. I didn't make too much of this but my curiosity about Linda's panties caused me to pick them up and admire them. Immediately, it was clear that her panties were quite wet and that she had masturbated wearing them. I could smell the sweet aroma of her arousal. Of course, I became immediately hard as a rock and couldn't resist masturbating, rubbing her wet juices against my cock. I came in a short time, spewing my man juice into her female juices!
I can't remember a time that I have ever been more aroused.
Since then, Linda sometimes teases me, giving me a view of her pert titties and stooping over so I can get a good look at her fine ass. It seems like she is doing it on purpose but I haven't taken the chance of acting on my suspicions in deference of my marriage to my wife, who I love and respect. I have been tempted though, believe me!