When I was a little kid I wore almost nothing but those loose shorts with an elastic waistband. They were comfortable, and about all my mother bought me to wear. When I was 6 I went to the pool, and wore my bathing suit underneath my shorts. When it came time to go home, I took my wet suit off and just put on the shorts, without any underwear. On the short walk home (we only lived a couple of blocks from the pool) I noticed how nice it felt to be hanging free. It felt good with my little penis rubbing on the soft cloth of my shorts, instead of being confined in tight underwear.
I started going around without underwear a lot, and it was my little secret. I found myself getting little boners pretty often, especially if I rubbed up against something. Pretty soon I was rubbing up against anything I could find if no one was around to see me. If I was reading or doing my homework, I would often lay on my stomach on my bed, and slowly rub up and down, and my little boner would tingle. Then one day when I was 8, I was doing that for a while, and it kept feeling better and better, so I rubbed a little faster and harder. I felt a strange urgency, and soon I forgot about what I was reading and was rubbing myself on the bed in great concentration. Suddenly I felt a throb, then a pause, then several more throbs in quick succession, and the feeling was incredible. I just lay there panting, reveling in how good it felt. I had no idea what was going on, but I knew I liked it.
Afterwards my penis was so sensitive to the touch that I had to put underwear on to hold it in place. I remember thinking about it the rest of the day, and was eager to try that again when I went to bed. When I did, I pulled my pjs off under the covers, and humped my bed again, and again got this incredible feeling.
Well, that was my start. From then on, I did that at least once every day, sometimes two or three times. Over time I found other ways to do it, particularly when semen made my old way a bit messy to clean up, but to this day my favorite is the way I discovered the joys of masturbation when I was 8 years old.