My sister in law stories are tame compared to many as no actual sex has ever taken place, just some sexy moments. She is the one I mentioned in the Danger Wank thread. She is a petite little thing, just over 5 feet, maybe 105 pounds but she has a great rack, a D cup. Unfortunately she doesn't usually show them off.
https://forum.oneclickchicks.com/show...5&postcount=28
One time my wife and I were at her mom's house when her sister was over to get their opinion on some cocktail dresses for some function she had coming up. Most of them were nice but conservative. Then she came out in a little black sleeveless and backless number that showed off her cleavage quite nicely. Not only that but because she had taken off her bra for this one there was also a bit of side boob in the rather large arm holes. My wife noticed my eyes popping out of their sockets. She laughed and said “well I think this one has my husband's approval”. I nodded with a big smile and said “yes, I can find nothing wrong with this one at all”. My wife and sis in law both laughed and decided it was a bit more revealing than was appropriate for this particular function.
Another time at my mother in laws for some holiday, my sis in law and I were doing dishes, me washing and her drying and putting away. When she squatted down to put some pots and pans away I got a nice peek down the back of her jeans, with her bright blue thong.
One Christmas I was sitting to next to this same sister in law along with another sis in law. They were discussing an upcoming trip one was taking to Cancun when they got to talking about bikinis and then to waxing. I soon knew one was totally bare while the other had a landing strip. Then they remembered I was sitting there and they got embarrassed that they had over shared information. I ensured them I didn't mind at all.
Like I mentioned in my Danger Wank story my wife knows I find her sister hot ( after all they look almost like twins other than my wife is six inches taller and has smaller boobs). My wife has surprised me a few times by including her sister in dirty talk while we are having sex. Saying things like “do you want to eat her pussy while I am riding you” or 'I want to lick your balls while you fuck her”. This talk always heats us both up, pushing us both to orgasm.