Me and my best friend in high school did everything together. We were the kind of friends that told all our secrets to each other and spent every weekend at either mine or his house. Whenever we would be hanging out we would get this thing going where one of us would expose our penis and call the other guy's name so, of course, he would look over directly at the other guy's penis. The guy would then laugh and it would go back and forth all afternoon with us exposing our dicks to each other.
One time we were doing this late nite at my house while we were watching some porn, so of course being teenage boys everytime we exposed ourselves we would get more and more hard because of the naked ladies on the tv screen. Well I finally got to the point where I was leaking precum and feeling too good to not jerk off. So I just left my cock out and began to stroke while watching the tv. At one point I looked back and saw my friend was stroking also. I have an average cock, fairly thick and just over six inches long but my buddies must have been a good inch longer and thicker, it was my first time seeing a hard cock in real life and it turned me on more than I thought possible.
Right about then I began to cum and it sprayed all over the carpet in my living room. It was one of my more amazing cums up to that point. The next day I was lounging in the living room watching tv when my mum came in. She noticed some spot on the carpet and reached down to see what it was, of course it was all dry but she noticed the pattern it was in and looked back at me and smiled as I sat there incredibly red faced, but that is another story.