This is something that happened merely hours ago from the time I am writing this.
My cousin stays with my family and I the majority of every summer, this summer is no different. He has made a few friends in my neighborhood and today his best friend was at the house, they are both 12 years old. Hours ago, not expecting to see anything, I walked in his room to ask him a question. Apparently he thought I had left the house already because when I got in his room he was lying on the bed with his legs dangling over the edge, and he was shirtless, his underwear was at his ankles and his genital area was covered with white lotion. (no, not semen). His friend was kneeling next to him and he had on his pants but his penis was sticking out of the fly and also covered with lotion. With one hand his friend was lightly stroking his own penis and with the other he was fondling my cousin. He asked 'Do you like me to go fast or slow?' No sooner than he finished his question he noticed me in the door way and said 'Oh Shit' he grabbed his shirt and ran out.
I told my cousin that he shouldn't be embarassed and that I had done the same stuff when I was his age, unfortunately that is not true but it did make him feel better.
He got on the phone a little while after the incident and was telling his friend that I wouldn't tell anyone, or call them gay and that I understood and that it was no big deal.
My cousin was almost right, I will never tell anyone and I understood, but it was a big deal. It was a big deal because that 10 seconds that I witnessed gave me an image I can use for the rest of my life to get off on.
I'm not the kind of person who would ever join in with 12 year olds, but from this day forward I may never be able to look at my cousin with out thinking about what happened, and wanting to masturbate on my own.