When I was 14 my younger sister and I shared a bathroom. It was those 'jack and jill' types and we each had our own room. It was about 8am on a Saturday (I remember EVERYTHING) and I entered the bathroom. I could hear heavy breathing in her room and could not resist spying. Her door was unlocked and I cracked it open a bit. There around 6 feet away was my sis on her back legs opened masturbating. She was staring at the ceiling and had a face like she was trying to read something far away. Her panties were on and her night shirt did not cover her at all down below. Her hand was inside and it looked like she was using two fingers to stimulate herself. Soon her fingers moved quicker and her white legs opened wider and she had her orgasm with a wide open mouth and quick breathing. She started to get up and I got back in my room fast. After that day I wanted more. I listened many mornings and was amazed at her frequency. I watched her hump objects she had in her room. Once she was facing the door when I opened it and I had to shut it again. I only remember seeing her eyes closed as she grinded herself into her pillow. The first time I knocked when I could hear her breathing and she yelled out to hold on. She came to the door in her night shirt and I said I wanted to borrow her CD player which I knew was not in her room. She got pissed off after a while of looking and tackled me to the floor. This was not uncommon for her and I found it quite arousing at the time. I quickly realized that every time the area between her legs was pushed against me, she would get that dreamy look on her face. I let her pin me and she was strattling my thigh repeating things like 'Are you gonna quit bugging me' . I just kept quiet and she had all her weight on her privates pushing into my leg. Within a minute she fell onto me panting into my neck and let me up. Her metal braces would leave marks on my neck I recall.
From then on she would seek me out in the morning and tackle me always resulting in her orgasm. I frequently entered her room and sat on her pelvis before she woke up and she pretended to sleep. Eventually her legs opened and her pelvis would thrust up to meet me. She would have her head turned and eyes closed but her breathing would quicken and I could study her face. Her orgasm came when her face scrunched up and her panting was very gittery. I longed to see her masturbate herself again but since she was using me, I never did. After a few months it stopped and she began locking her door. And that was that.