Good question, I think that for all of us we discover masturbation by accident.
For me it was until I was 10 years old. But since I was 7 when I exercised, especially football, the constant rubbing of my glans with my underwear made me feel ticklish like when you really want to pee.
It always left a stain on my underwear, now I know it was precum. This was always the case but the excitement of the game along with the adrenaline caused me to ignore it. As I said in another comment, one day before a game, to avoid friction burns on my penis, I always put petroleum jelly on it.
My routine was always to bathe and change, but first I would put on cream and sunscreen, and lastly I put jelly on my penis. When I was putting on I felt intense tickling. But due to lack of time I ended up changing.
When I returned I still had in mind when I bathed what I had felt, so I grabbed the jar of jelly and in the bathroom I put some on and one thing led to another,That made me have a dry orgasm.
That time I was very scared by the sensation of spasms and seeing how my penis vibrated. Pure innocence, when I was able to relax my body, a transparent liquid came out of my penis. I took a bath and put on my pajamas, I didn't talk to anyone about it.
I didn't do it again until I was almost 12 years old, while on vacation I started to be attracted to girls, especially because in Spain it is common that they don't wear bras go with nothing on the beach other than their bottoms.
I noticed that seeing them and imagining them gave me a more intense erection, you could see the tent that my swimsuit made.
That day I was bathing and grabbed some of the body cream and started masturbating imagining the girls. When out of nowhere I had an intense spasm and I felt very intense tickling. My penis spurted a stream of white liquid, my first cum. As soon as I could, I got up, cleaned myself, and put on my clothes. A few days later I told my older brother and he was the one who described to me what had happened to me.
There I discovered that my penis was not just for pee