This happened when I was 15

I used to go visit my best friend at his department, their parents just split up so he was alone for several hours at a time because of his mother´s work, so we hanged up playing videogames and reading comics.... you get the picture, right?

Well in one of these visits he tell me that he has a cd with porn that her sister´s boyfriend had given to him a few months back, so I asked him to put it in to watch it, nothing major for today´s standard, just several short clips downloaded from internet and such.

A couple of minutes (and videos) later I have this big boner in my pants (I´m 6.9 inches now , but back then I was like 6.4 or so) and I´m not very tall so it was very noticeable, he sees this and begins to joke around if I needed to go to the bathroom for "relief" or something, I told him that "who knows maybe I´ll go" and then he says "well, in that case I dare you to go!!"

Taking his challenge I go to the bathroom, but he insists in coming with me so I don´t cheat or anything, once inside I pull down my zipper and began the good old stroking on myself, He is like "dude you are large (I wasn´t aware of it before, but it was a really good morale booster back then)" and he then opened his zipper too and began to masturbate right next to me, he was like 5.8 or so, after a couple of minutes he comments on my technique like: "why don´t you try pulling slowly the skin back to the shaft and then let go (Both of us are uncircumcised)" and then he says " may I?, like this" and he grabs my dick and begins stroking it very slowly, quite an unusual feeling and I´m like "wow it feels good, but have you tried doing this?" and I grab his dick and began to make a rosy palm with it (pulling back the foreskin and rubing his glands with the palm of my hand) and he´s like, "dude it hurt a little but don´t stop now", and I say "don´t you stop either", we keep going five more minutes and he told me that he was about to cum, so I was and we changed to the fist and kept masturbating each other to orgasm and we aimed our penises so we ejaculate in the toilet, I came first and he did a few seconds later.

He looks at me and says "that was cool, I was seriously thinking you would chicken out, can we do it some other time again?"

Unfortunately he moved away a couple of months later so we didn´t get a chance to repeat it again, a true pity for I was eager to repeat it...