I have been masturbating ever since I was 13 years old. My sister, whose name was Mary Grace, always had a nice body. She was 16 at the time, she was a brunette, with hazel eyes, slim body, and a nice 36b breast at the time. I was a young 14 year old boy, with a generous amount of pubic hair and just some fine armpit hairs. I had about a five inch penis.
Our living room was arranged so that if you were on the stairs you could look around the corner and see the couch, facing the wall to the right. One particular day, me and my sister were home alone, and I was walking down the stairs, and then I noticed my sister laying on the couch facing the opposite way of me. She did not know I was home because I was usually at football practice on Mondays, and we lived across from the school so I did not need a ride, I just walked. Now, this is probably the opposite of what most stories are on this site. Believe it or not she was actually in my clothes. She was in my boxers and one of my white t-shirts with her bra and panties on the floor. I was surprised that she would actually do that. She never took the boxers off, but she did remove the t-shirt. I saw her nice, pretty much developed breasts. By this point I had a buldge in my pants and my heart was racing because I was scared I was going to get caught. She started to masturbate. Her right hand was inside of the boxers and her left hand was on her right nipple caressing it. I just about lost it. I had never seen my sister like this before.
Eventually after about five minutes, she started to breathe harder, and her chest was rising higher. She was starting to pant and softly moan. I was about to cum in my pants right then. Then all of a sudden her hips rose in the air and then she started to moan and gasp for air.
After it was all over she put her panties back on and the other clothes and put mine in the laundry, and decided to go take a nap or something. I went to the laundry and picked up my boxers, and saw that there was a wet spot in them about the size of a tennis ball. I was really turned on. I went up to my room and had an orgasm within two minutes. But I wasn't done with my sister.
Later that night, when my parents would not be home for another two or three hours, I decided to have a little fun with my sister.
I was going to let her catch me. This really turned me on just the thought of it. I left my door cracked about two feet from the frame, and was facing toward the wall away from the door. Then I made this really loud noise so she would hear it and come out of her room. Then I sat down, completely naked, just jacking off. I heard her come out of her room and down the alley way. I heard foot steps and then they just stopped. I knew at that moment that she was watching me. I kept going until I came on myself and then turned around and saw her, and pretended to be surprised and cover myself up. She said that she was sorry and then she walked away.
That has been the best day I have ever had so far and I hope something between us will happen again. Thanks for reading.