Many of my first sexual experience we're shared with a distant cousin that I grew up with. We both started masturbating around the age of 13, and as shared most things, it was only natural to share this, as well.
At first, we simply played doctor, checking out each others equipment. Soon, however, we would sneak off to be alone any chance we could, and would immediately strip naked. Our experimenting began slowly, touching each other, lying naked together and wrestling, etc.
As we each developed our own techniques to jack off, we would share them, and we began to stroke each other to orgasm. By the age of 14, we had evolved elaborate play. I especially enjoyed when he would lie on his stomach, and I would place my little penis between his butt cheeks and dry hump him - we were trying to figure out the ins and outs of the 'sex' we heard about, and this was a fun simulation! We were just entering puberty, and so we didn't have much hair yet, and the smooth feel of his skin against mine was exquisite. We often talked about something we had heard of called a 'blowjob', but though tempted, we were too intimidated to try.
The most memorable experience was during one sleep-over, when we were 15 or so. We were on the bed, playing a game of strip poker, and after a few hands, we were both buck naked, and unsure of what to do next. Now was my chance! I lightheartedly suggested that we play one more hand, loser sucks the winner. After some coaxing, he agreed...
I think I lost on purpose, just so I could finally take that smooth little willy into my mouth, like I had dreamt of for so long. When I threw down my losing cards, he leaned back, spread his legs... and I nervously bent down, taking his limp penis into my mouth. He stiffened quickly as I sucked, and to my amazement I REALLY enjoyed it. He moaned a little, and tried to push me off, but I kept going for as long as I could.
He didn't need too much encouragement to reciprocate, and I couldn't imagine anything feeling better than it did as he sucked me.
Soon thereafter, we both found girls, and that was the end of our innocent play. Fond memories, though, and a nice introduction to the joys of pleasuring yourself and others!