I was a 15 year old boy while my sister was 18. One day, I was laying on my bed masturbating and I thought I locked the door, but I guess not. I was laying on my back masturbating and I rolled my head over to one side to see my sister standing outside my door watching me. I have no idea how long she was there watching. The door was just barely opened, so I couldn’t see what she was doing, but she was there. Right about the time I saw her, she pushed the door opened a little bit, and I freaked out. I grabbed the towel that was next to me and tried to cover up my private area.

After I did that, I turned to look to see if she left, but she did exactly the opposite. She pushed the door opened ever further, and slowly came into my room. She turned and shut the door behind her and slowly walked over to the bed where I was at. I was speechless. She walked over to the bed, and right up to me and asked, “what are you doing?” I was so shocked that I just said, “nothing”. She looked right into my eyes and just smiled when I said that. Then slowly, her eyes went down my chest and to where my privates were (that were still covered with a towel), then her eyes went back up to meet mine, and she said “I know what you were doing”. Again…I didn’t know what to say, so I said nothing. I expected her to leave at this point, but she slowly turned and walked to the end of the bed and sat down….facing me. She was wearing a loose skirt and a button shirt that was partially unbuttoned. My sister is really beautiful and has lots of guys after her all the time.

Anyways…she sat at the end of the bed with her legs crossed and a smile on her face. She sat there for what seemed like forever, but was probably about 15 seconds or so….then she unbuttoned one of the buttons on her shirt. I was thinking WTF? Then after a long pause, she unbuttoned another button on her shirt. I could see her cleavage at this point (and that she wasn’t wearing a bra). Then she asked in a really light voice, “are you going to tell me what you were doing?” I said no. She just smiled again, and slowly started opening her legs. She was wearing a really loose skirt, so it didn’t take long for me to see that she wasn’t wearing any panties. At this point…still too shocked to speak, I knew in my mind that she was toying with me. After spreading her legs enough to expose herself, she slowly raised her hand back up to her shirt and unbuttoned another button on her shirt, exposing most of one of her boobs. She was still smiling…and my heart was pounding. I didn’t’ understand how I could be so shocked and getting turned on at the same time. Right about that time….she unbuttoned the last button on her shirt, and slowly pulled her shirt opened, exposing both of her perky boobs. I was so hard.

She started rubbing her nipples with one hand and grabbed my hand with her free hand and put it on her leg. I was so turned on, I couldn’t help it…but my penis got really hard and made it’s way out of the towel I had laying on top of it. It was so hard...and she just smiled that I finally let go of being scared about her seeing me. I started masturbating again….with her watching me. She took her hand from the top of mine that was still on her leg, and she ran it up her skirt, and started touching herself. She was rubbing herself, and I was stroking my stuff looking at her. She was breathing really hard and so was I. Her nipples were so hard, and so was my ♥♥♥♥. I could see down there that she was REALLY turned on....her fingers were really wet. It was really strange and really HOT. I was so turned on that I came in like 30 seconds. I think some of my load even shot onto her leg. But after I finished…she just got up, still smiling, buttoned her shirt and walked out of the room, closing the door behind her.