Same. I used to rub my dick on the floor of the bath until it got really sensitive and I couldn't do it anymore. When I did this it'd get hard and it would actually start hurting so I'd have to finish quick before it got too hard.

Then I realized I could do it anywhere, not just in the bath. So I started doing it during class when we had to sit on the floor. I did it during recess and PE.

Then, at some point, I hit puberty. And I realized the thing I was doing all those years was just masturbating. And it's hard to clean up if you jizz in your pants.

I still do masturbate prone because I can do it anywhere with virtually no sound. Just cover my dick with TP.