Originally Posted by pudendum
I agree with you that low level clamping or pumping works (that is if you and I agree that low level means at a lower level of erection; 50 - 75%). In this lower level erection, you can increase tension by increased radius and pressure on the unloaded (or lets say less loaded) tunica (clamping, pumping, squeezes, jelqs, slinkies).
I don’t think I have ever heard of anyone getting success with pumping at 50-75% erection, usually I hear the opposite, that they don’t get results unless they keep a high level erection.
I think that an unloaded tunica is easier to produce derangement of fibers in, but not while isolated from manual manipulation in a cylinder. It when you can induce ADDITIONAL strain to the fibers, WHILE UNLOADED, that allows the derangement to occur.
I believe that the the derangement force while pumping IS the net stress force on the tunica which is the sum of the internal expansive force PLUS the decreased atmospheric pressure (as has been extensively discussed here).
So if you have a low level erection, the stress on the tunica drops below an effective range. That “opinion” is based on personal experience, and responses from many pumpers on this forum.
If you were somehow able to reach in the tube while keeping the vacuum, and pull, twist or bend the penis, then yes, I believe you could get results, but as that is not possible.