I was at my cousins' house about a year ago and they wanted to read me a story in their playroom. Since I had nothing better to do, I decided to do it. About a quarter of the way through the book, I got extremely horny (I hadn't masturbated in a few days.) Whenever my cousins weren't looking I put my hand in my pants and felt my hard penis.
Both of them had to go the bathroom at one point and I saw this as my chance. I put my hand in my pants and started stroking my hard cock. They came back a minute later and told them I had to go to the bathroom now. I quickly sat up and walked to the bathroom. I pulled down my pants as fast as I could and started jacking off. As I was about to cum, my cousin walked in on me. He wasn't old enough to know what I was doing so I wasn't too freaked out. I told him to go back and finish the book and I'd be there soon. He closed the door and I finished my session.
The orgasm was one of the best I ever had. I went back to the playroom and finished the story. After dinner that night, I jacked off again.