I’ve been pumping for years. Blew through my newbie gains years ago. Used to do high pressure for 20 minutes, but after reading advice here on Thunders, I’m doing 1 to 1.5 hours at 5 Hg. Everyone is different, but in my case I have build up resistance to the pressure and do not get edema from 5 Hg even after 90 minutes. Definitely makes me feel better to the Mrs.
I’ve been down that road. Even at 30 minutes every other day started slowing down my gains. I did 1 hour, sometimes more, at 5 inHg every other day for some time without gains.
I think keeping gains coming after a certain point relies on keeping the penis from becoming too fibrotic. When it becomes fibrotic it needs more and more force to expand and just upping the vacuum pressure and time eventually won’t work since it increases the fibrosis.
I experienced this in the extreme from clamping, I reached a point where I could not exert enough force to expand the penis any further.
With penis pumping specifically, there seems to be something that causes gains to be reduced after 20 minutes. I’m not entirely sure what it is, but it seems self apparent from my experimentation with various pumping durations. I think it might be that the blood flow into the penis is insufficient and the interior of the penis goes hypoxic (more hypoxic than normal), causing fibroblasts to start producing collagen.
Starting: 7"bplx5.2" 2017 (shrunk from disuse)(originally 8"bplx4.5", gained to 9"bplx6")
Current: 9.0"bplx6.125" 2020
Goal: 11.5"bplx7" 2021.