Since you brought this thread back up, let me also contribute to it again.
There have been quite some improvements regarding my addiction since I last wrote here.
For that, I mainly used two approaches:
I designed a kind of reward system - I normally am completely forbidden from sexual activities, but can earn them for good behavior (specific kinds for specific deeds). And for each 1.5 months of keeping to that system, I get one day of using porn (which otherwise is completely forbidden with the exception of erotic hypnosis files).
Yes, that means that I'm now in a BDSM-relationship with myself
That works really well, and I am really happy with it - less wasted time, being able to use sexual desire to motivate myself to do specific non-sexual tasks, ...
The only problem was that I would still when getting aroused feel the urge to do something about it, instead of simply enjoying it.
Therefore, I decided to use some hypnosis to help myself with that issue. It's a hypnosis file I've known for quite a while but I had considered myself not ready for it. But now that the desire for masturbation was the only negative aspect remaining of how I felt about sexuality I decided to give it a go. It works by having one mentally connect masturbation with feelings of nausea. And it works really well, I listened to it 4 or 5 times a few weeks ago, once a day at most, and still now just writing this makes me slightly queasy.
I have been careful to connect nausea only to normal masturbation, so other ways of getting sexual pleasure are still open to me. I even removed some parts from the file that I was not comfortable with or that seemed unnecessary for my situation.
And well, by this amateur aversion-therapy I now am masturbation-repulsed instead of -addicted, and I couldn't be happier. It's awesome to be horny all the time and nevertheless not feel any desire to masturbate. I hope this is permanent.
And other ways of getting sexual pleasure are enticing enough to serve as motivations but do not cause such strong cravings. Since they involve things besides my own body I can also much more easily think of them as something that I first need to earn.
If anyone reading this considers this something they want to try out themselves, be aware that I would only recommend this if you have done enough reflection on how your psyche works and are confident that this will be compatible with it, because I can easily see this causing damage to someone not prepared for it. The file even makes sure to try and throw one out of trance if one isn't entirely certain. So only search for it and listen to it if you really know what you are doing to yourself and truly desire to basically mutilate your sexuality in this way.