I confess that I have always been attracted to my wife's younger sister. She is a very hot brunette, 5' 4", one hundred and ten pounds, with a fine body. She was only eighteen when I married her sister and used visit us quite often, even after we got married. One weekend, I had gone out partying along with my wife and her sister. We really had a lot of drinks that night. By the time we returned home, all of us were barely able to walk. We were so wasted that, without realizing it, we all landed up on the same bed. My wife started feeling horny after some time (I guess it was the wine) and started working on me. She wanted to have sex with me even while her sister was sleeping barely a few feet away from us. To cut a long story short, I made love to my wife most passionately that night. All this time I was eyeing my sis-in-law's thighs and imagining she and I together. From the corner of my eye, I could see that her gown had been raised and her red panties were quite visible. Later during the night while holding my wife tightly, I was tremendously excited. There was no point in waking up my wife as she was not going to wake up for the next ten hours at least. Then I realized that this was the chance I have waiting for, ever since my wife's sister came to stay with us for the summer holidays. I slowly crept towards her and turned on the night lamp. She was fast asleep as expected and lying on her back. I then relieved myself on her, but didnít have actual sex with her. I then went to bed. When she woke up the next morning, she went to the bathroom for a shower, not realizing what had happened that night. As she freshened up and came out, I again began stirring, but I couldn't do much about it then.