I think it's fairly well documented that excessive use of porn causes the person to need an ever increasing potency, in order to get the same effect. Your mind needs to be titillated and encounter things that feel new in order to get the kind of biological/neural/psychological response you want, and the more you consume the harder it is to find things novel. Maybe you're just masturbating too often, and as a result it's harder for you to reach that level of novel experience each time?

Not saying you should be completely chaste, but maybe you're just jacking it too much for your particular biology/neurology/etc. If you dial it down a bit you'll probably find you have more control over it

And just from a like therapy perspective here, you shouldn't think of this fetish as "terrible", or something that you "loathe". Yeah I feel gross about it too sometimes, but as long as nobody real is being harmed then who the hell cares what "normal" is. Don't judge yourself for having an unusual kink, just accept it while also remembering that it's not conventionally accepted. And obviously don't do things like this in real life