One summer I was staying at my Dad's business partner's house over the summer. His partner had a daughter that was 14 years old and I was 12 years old. I had a crush on Lisa as she was a cute blonde that I spent almost every waking hour with and slept with in the same room. Every afternoon we would sit and watch TV in the living room when our parents were at work.
After several weeks I started to notice that she would sit down on the chair and cross her legs and start bouncing them rhythmically together. It took me a while to notice but when I did it occured to me that she did this several times a day every day since I had been staying there. After she stopped, she would then leave the living room and go to her room and lock the door. She would stay in there for over an hour. After watching this pattern develop I decided to find out what she was up to.
The next day when she started to cross her legs and bounce I decided to act like I was going to the restroom. I went instead to hide in her closet, since I knew that she would be there soon. Before I knew it she came in and looked around, almost looking to see where I was. She then returned and locked the door behind her. As soon as the door was locked, she laid on the bed, lying on her stomach with my rolled up sleeping bag underneath her hips and pussy area. She then spread her legs open wide with her legs bent at the knee. She started flexing and thrusting her legs back and forth at a rapid pace. Her breathing started becoming heavy and the friction of her legs thrusting back and forth could be heard. She was wearing faded blue jeans and no shoes, as I could see her toes curling inward as she continued. I was not sure what I was witnessing at the time but my senses clearly knew it was sexual. I now know that she was using thigh pressure to masterbate.
My dick was as hard as I have ever known it to be. My heart was pounding, as I wanted to jack off so bad. When she was doing this both her arms were holding a pillow over her head tightly, then when she was about to come she moved the pillow to expose her flushed red face and dazed and glossy eyes. The sound of the friction and her breathing was enough to make me go crazy. After she was done, she rested for a few minutes and then did it all over with the second time taking a little longer but seemed more intense. She then got up and picked her wedgy out of her pussy and left the room.
I would hide in the closet many more times jacking off watching her. One day she finally caught on that I was never out of the bathroom until after she was done and she searched the house looking for me. I was so scared. I tried to sneak out of the closet and as soon as I did she saw me and realised I had witnessed everything. Not a word was spoken about this. She still continued to masterbate in front of me by crossing her legs watching TV while she sat down, probably because she didn't think I had a clue what she was really up to, but I did. Her face would turn red and she would grunt when she came. Heck she would do this for hours. I would have to run to the bathroom and jack-off because I couldn't take it.
One day I even put on some of her panties she had just had on when she jacked off. The panties were wet when I put them on so I used the wetness to masterbate with. I was so turned on by watching this experience that I often used to wish I could turn into a girl for a few hours to try this out since it looked like it felt so good. It was really something to watch a girl masterbate when she thinks she is completely alone. I found this to be just as sexy if not more than if she had been completely naked with her pussy exposed.
Later that summer we ended up helping each other jack-off. I would sit on her butt or lower back and provide weight on her pelvis, so to give her more clit stimulation and hold down the pillow over her head. After, she would use her fingers and place my cock between her index fingers and thumb and rub back and forth until I came.