I was probably about 11 years old, and had experienced getting "hard" for some time. But, had not experienced "cumming" yet. A (guy) friend and I started meeting after playing basketball for "experimental" sessions in an unused, and mostly dark, racquetball court at a local recreation center.
We would pull down our gym shorts and then our white, cotton underpants. Both of us would be very, very hard, by this time, and our dicks would stick straight up, almost touching our stomachs.
Our penises were very similar in "direction", although his was probably a little thicker, and longer. I remember his penis was very hard and bent almost arching back to his stomach. We both had just a little bit of pubic hair.
I remember this as if this happened just yesterday! At first, we would just rub our penises together. His penis was soooooooo warm, hard, and purplish at the head! It felt so good just touching each other's penises and rubbing them together. It felt velvety smooth, and warm.
He asked me if I had ever cum before. I didn't quite know if I ever had, but didn't think so. He said that sometimes he oozed some white, milky-white fluid after rubbing his penis for a while. I said I didn't think that had happened to me yet.
One of the times we met for a "session", I lay down on the floor, and he lay on top of me. We rubbed our hard penises together. WOW, it felt soooooo good!
We had been going for several minutes, when all of the sudden I felt like I had to pee. I got up quickly, telling my friend I had to pee. He touched the end of my penis and felt a small amount of warm, milky-white, sticky fluid. He said that is "cum", not pee. I felt it also, and rubbed it between my fingers. That was my first time!
We had many other sessions together, but later grew away from our experimental sessions as we became older teenagers.
I later had many mutual masturbation experiences with a guy cousin, who was the same age as me. We had many, many mutual masturbation and penis-rubbing experiences. He actually taught me how to masturbate, and I still use the same technique to this very day.