I had noticed for some time that my wife's twin sister seems to put on a show when I am around. Leaving her blouse open so I can get a good view of her tits or leaning over showing me more than usual. On several occasions she has spread her legs giving me a good shot of her upper thighs. Recently my wife and I and her sister and her husband were sitting watching TV. My wife and brother in law were sitting to the side in chairs. Me and my sister in law were both sitting on the sofa, although not close. I happened to notice that she was looking at me in the mirror above the TV. Now we both could see each other in the mirror but our spouses could not see us since they were sitting at an angle. I noticed her staring at me and my eyes happened to drop to her knees and when they did I noticed her knees parted slightly. I kept looking as she slowly spread her legs more and more. Finally when she stopped her legs were spread and I could see the crotch of her white panties. I made no bones about it. I would look her in the eye through the mirror and then look down at her panties. This went on for a while but finally she got up and excused herself to go to the bathroom.
A few minutes later she returned and sat back down. I noticed her legs began slowly to spread again. I was sitting there waiting for her panties to come into sight but to my surprise all I could see was black hair. She had taken her panties off while in the bathroom. My dick started getting hard so I excused myself and went to the bathroom. There on top of the hamper were the panties she had taken off. I had locked the door so I picked the panties up and looked at the crotch. They were still wet and the crotch was soaked with her juice. I smelled, licked and sucked the crotch of her panties while my right hand was jacking my dick as fast and hard as possible. It didn't take long until I was ready to cum so I held her panties over the head of my dick and filled them with hot cum, shooting it directly into the crotch. I put the panties back where I found then and zipped up and walked back in and sat down.
We continued talking and watching TV and about two minutes later my sister in law said she needed to get something in her bedroom and show her sister. I thought she was gone from the room a little longer than it would take to walk to the bedroom but when she returned she had some pictures she wanted to show her sister. She handed the pictures to my wife and sat back down on the sofa. Pretty soon her legs were spread and she had put her panties back on. It was the same pair I had just cum in. I could tell they were wet from her pussy juice and my cum. After I saw she had her panties back on I looked at her eyes and she smiled and gave me a quick wink.
I don't know what she has in mind or how far she will go, but I have always wondered what she would be like in bed, since her and my wife are twins. If she keeps this up I'm sure going to try and find out.