Cutting down on masturbation definitely helped me gain because it allowed me to concentrate fully on PE. Also, I find that I will masturbate for a long time…45 minutes to two hours at times - that intensity is usually far too much in addition to PE. I would often get negative PIs doing this. Even a little masturbation could tip a good workout into negative PI territory.
In fact, I’m on a week-long decon break right now and I will be starting PE back up with the newbie routine (I have been trying to pump, but I’ve finally given up. I believe it is too intense for me and I risk injury). The newbie routine is the only thing I’ve gained from (along with some dry jelqs).