Holy shit. I don't do this anymore, but I started "masturbating" when I was seven years old by grinding my dick against a hard surface or corner until it hurt or felt good or both. I NEEDED a hard, unforgiving surface like wood that would make me feel pain. I always fapped without getting an erection, in fact I COULDN"T fap when I got an erection, I tried to suppress it and grind my dick down.
Before I could maintain an erection or coom that's what I did, I've been fapping since before puberty. I was ALWAYS sexually subby too, I imagined pretty girls dominating and controlling me in feminine ways the whole time. Let's not even TALK about the fact that my active child imagination (I NEVER watched porn until I was 13 by the way or even talked to my "friends" about sex, so this was ALL my imagination) I liked to imagine being shrunk down and forced down a girl's ass or vagina. I started imagining it with guys' asses, too. For a short while, I actually started preferring guys, before puberty advanced to a later stage and I thought that was disgusting.
Gradually, the women in my fantasies became more masculine. When I matured a little around age 11, I started doing it in in my underwear and just pressed down on it against my body half the time, and GRADUALLY phased out the other method. By this time, I had lost my attraction towards men, and started imagining more complex fantasies, things that I now realize are considered by normies to be "really disgusting fetishes" that I don't know if I want to get into, for example, I enjoyed the thought of being forced to eat a girls' poop. I called this activity, "rolling my penis" until I learned the proper term for it around age 13. Around age 12-ish I started really getting into Pokemon Rule 34, but I didn't like using porn and would rather just use shitty in-game images or AT MOST softcore, non-naked shit.
Anyway, when I was 13 I decided to start "masturbating PROPERLY" and learning to do it the "normal way". It was a gradual process, but from the first time I masturbated "properly" ("properly" is a relative term, meaning I actually sat down, had an erection, and rubbed it, instead of what I was doing before).
To this day, I masturbate from grabbing a piece of skin from the underside of my circumsised 4.5 inch monstrosity and vibrating up and down, side to side in close movements. I also occasionally lay down on my belly and compress and softly move it back and forth. These methods still aren't "normal", but they're MORE normal.
Over time, my fetishes because physically tamer and the women more feminine in my fantasies (once again always preferring my imagination to porn, but will occasionally try and find a good softcore still to look at), but psychologically more disgusting, so now that I have a fetish for a woman who will destroy me and my life in every way possible if I let her, maximally. I still like femdom, and enjoy the thought of being a sub bottom.
Also, I heavily relate to femdomcels like @Blacktarpill, I think I side-effect of being masochistic is wanting to hurt one's own dick, and therefore developing weird masturbation habits.
I had both parents, both white Evangelicals, my dad was super strict, I always had depression and tried to kill myself and ran away from home, was at the bottom of the social dominance hierarchy at school and got bullied, etc. So don't go accusing me of "not having a father figure" and "being soy because I never got bullied". I got plenty of that shit, way more than normal.