This happened to me and my friend, we are both 15. He was spending the night. My parents went to dinner with friends and they weren't going to be home till late. So it was just the two of us. Around three in the afternoon I said let's go for a swim. We have a swimming pool in the back yard. He said that he didn't have swimming trunks. I said that's ok, lets go nude. He said yes right away. We went in the pool and started to play around. We didn't notice at all that we were naked.
Then I said that I had to go to the bathroom he said ok and I went. When I was coming outside again he was sitting on the side of the pool. Then he said I just noticed how nice a cock you have. I told him yours looks nice too. I asked him did he ever jack off with anyone. He said no, I told him I didn't either. Then he said you can do it to me if you want. I said, if you let me do you then. So he said ok. We jacked off a few times and then went inside and looked at some of my dad's porn and did it a few more times. We still stay at each others homes on the weekend and do it every chance we have.