Reminds me of my first experience. Pretending to be asleep at my friends house, he slid his hand between my cock and the mattress. I started grinding his hand right away while he squeezed. Didnt take long for my pants to come down and kept on grinding his hand. His pants came down, i rolled over and he was grinding away dick to dick.
A friend of mine did that to me. I was laying on my back, he was on top of me. He said that he liked to rub his hard cock on my hard cock. He was enjoying crushing my cock and balls with all his weight. I wasn't able to stop him. I came without really being aware of it. It was a cool experience.