I was 12 when a boy on my block asked me if I wanted to see his dick. That led to me sucking him and a few other boys in my circle. Some really good memories.
I think that I was around 13. I had a friend the same age who I'd get together with frequently to play with each other's cocks. One day he told me that his brother had explained to him that a guy had to be sucked by another guy after he had sex with a woman (what can I say? I was naive). He told me that he'd go first if I agreed to try it. He was good to his word, so I took my turn. I've wished for years that I would have known what I was doing and could have made him cum.
