Prank Gone Wrong

When I was 13, my older brother was 17. We would prank each other all the time. One day I got home from school, and decided that I was going to scare the crap out of him, so I hid my book bag in my room and went climbed in his closet and buried myself with his dirty clothes (gross, I know but didn't think anything of it at the time).
While I was waiting for him to come home, I fell asleep. I don't know how long I was out, but when I woke up I opened my eyes to see my brother laying on his bed with a playboy in one hand and jerking himself off with his other. I was shocked, to say the least! I was scared to death to jump out now, and scared to move out of fear that he might notice me hiding there.
He was just laying there flipping through the pages, and stroking his dick. I didn't want to watch, but I couldn't look away! Watching him do that to himself was disgusting at first, but the longer I watched, the more I felt myself getting turned on.
It only lasted a couple of minutes, but when he came; he pinched the end of his dick to keep from squinting everywhere. Next thing I knew he got up and came to the door of the closet where I was hiding, I guess to find a rag or something to put it in, and he saw me sitting there. He jumped, I screamed, and his dick shot cum all over me!