I have seen some great explanations here of how people learned to masturbate, and their early experiences. Here's mine.
I don't know how old I was when I first started masturbating, but I know it was very young. Maybe 4 or 5. I do remember doing it, though. It is one of the few clear memories I have of early childhood. Here is how I learned.
I had a blanket that I had always slept with. It was like a terrycloth, but the loops of fabric were fairly large. From an early age I liked the feel of rubbing those loops back and forth -- they were kind of like knobs. I'd get them under my fingernails and rub them back and forth, and it was a comforting feeling. The funny part was that my little penis would get hard when I did that in bed for a while before falling asleep. Of course a hard penis is more sensitive than a soft one, so as I rubbed the loops on my blanket, I'd rub my penis on my bed. At some point I found that if I bunched up the blanket in my crotch, it felt even better, and I'd lay there and lightly rub my penis on the blanket. Then one day I thought it might feel better if I pulled my pjs down and rubbed my bare penis on my blanket, since it felt so good to my fingers. And I was right -- it felt great. I kept doing it and it felt better and better, then suddenly I felt a wonderful throbbing in my penis, and it felt great. The throbbing only lasted for a very short time, but the afterglow lasted much longer, and I felt very relaxed and happy, and fell asleep with my pjs still pulled down. That of course became a nightly habit, and I did it for several years until I switched to doing it on my pillow.
My mother always told people she was so happy that I never made a fuss about going to bed on time. Little did she know that the reason I was eager to go to bed was because I was looking forward to my little secret pleasure. I didn't know until I was about 12 that other boys could do that, too, when I saw my best friend doing it during a sleepover. That made me very curious, and I eventually found out that all my friends did it one way or another. I caught one friend doing it with his hand, and that intrigued me, and I tried it. I liked it, and once I started ejaculating, my hand became my favorite way of masturbating, since cleaning up my pillow was harder then just wiping off my stomach with a tissue.