When I was around 11/12, there was a night I could not fall asleep. At the time I had no TV in my room, so I was really bored. I also had never masturbated before, so I didn't have that pastime to fall back on. I got up to go to the bathroom and noticed my mom's bag of maxi-pads sitting on the floor. I'm sure I didn't know what they were for at the time, but I really didn't care.
My curiosity getting the better of me, I took one out and put it in my underwear right by my cock. It was really soft and felt very good when I pulled my underwear back up nice and tight. I went back to my bed and lay down on my stomach with my hands down my underwear. All this felt really good and I had a nice boner.
I started to hump it nice and fast and then I peed in it. It felt so good, all warm and wet. This pleasure went on for a while until I finally burst and had my first orgasm. It was amazing. I didn't know what had happened and I just wanted more of it. I kept on going, having one more orgasm and then promptly falling asleep. That was the first and most memorable time I have had.
Ever that experience the means I have been using varies, but has included incontinence pads and things like that, which I highly recommend for a try.