This thread gives me some hope.
I started masturbating prone from about 12-13 and have done so until today basically(26). From an early age I knew I was different because the standard way to jerk off is with one's hand and yet I could not do so and instead jerked off prone but I didn't know it was bad. I would jerk off pretty much everyday, at least once but sometimes up to three-four times. In fact I would often think throughout the day ahead of time about what I was going to fap to, maybe to this instagram girl or that scene or maybe a fantasy of a specific girl I know. I only found out earlier this year when I have some sensitivity in my testicles. Turns out that was unrelated, just a benign cyst, but when I started feeling problems my brother asked me if I masturbated prone and I said yes to which he told me to stop. It was only then that I started looking into it and found out how bad it is. I have tried since then to stop but I have not been able to go longer than two weeks without relapsing. Went six days and relapsed today.
I know I have caused serious damage to my penis through this. I am almost certain that I have damaged my penile suspensory ligament, possibly even tore it, through masturbating prone and even still I relapse here and there, making it worse. That will probably require surgery to fully heal. I also have some chafing on the left underside of my penis.
I've talked to two urologists about it and both were not aware of the issues with masturbating prone. So even though I knew it was wrong I took that as an excuse to keep trying. I would cheat and try to find ways to prone without doing damage like using a pillow to try from different angles but it still kept getting worse.
I really need to stop but man just going two weeks is hard, much less 90 days or 100+ like some of you. I am still a virgin, in fact I have never had a serious girlfriend before and this is really killing my confidence. Seems like I have a medical mountain to climb before I can even think about getting with a girl. Thankfully I don't really have a porn addiction. I like bondage but I generally fap to vanilla stuff like instagram or bondage scenes from mainstream media where nudity is rare. And most of the time I only use my imagination. So I still get aroused very easily, just letting my mind wander to such thoughts can give me a boner and I do not really have high standards when it comes to girls. But the downside is I get tempted to fap very often because of that.
I think the big problem for me is that I've conditioned myself to fap right before going to sleep since I would fap prone. So now if I go to bed my mind is already wandering to sexual fantasies and if I have insomnia I will be extra tempted to fap.