I was about 15 when this happened and my sister was about 18. Some of her friends were super hot and whenever they came over i was always so embarrassed to talk to them. Anyways, I decided to do something really stupid when one of them came over. I decided to jerk off to one of them. So while i was in the middle of it i realied that i left the door unlocked, but i didnt care enoguh to get up and lock it. So when i was done, I was so tired i didnt even get up to clean the sperm off my stomach. So there i was, laying on my bed with a puddle of sperm on my stomach. Then, my sister and her friend quietly came in. They were probably laughing their asses off but i was half asleep so i didnt hear them. Anyways, they came up to my bed and started poking fun of my penis. They were touching it and squeezing it, and this is when i woke up. I got SO RED. I couldnt take the embarrassment. When they saw that i saw them, they made the small penis sign with their two fingers to me and laughed their way out. The next day at school, one of the school cheerleaders came up to me and said what were u thinking? was that supposed to be funny? I didnt know what she was talking about, but then she showed me a picture of me on my bed naked with the sperm on my stomach. I was so embarrassed. My sister must have taken a picture of me. So now everyone at school knows my "little secret." The cheerleaders even made a cheer about it:"Hey there jason, You can see it in his eyes, In his pants, he orders childrens size!"