I’ve been playing around with a pump filled with water. The effects seem much better than with air (dramatically less edema and instant response to the pump, no constriction and very little force needed to achieve significant pull). Perhaps that would be a way to go.
The only downside is that after an hour or so, the point where the tube makes contact with the pubic bone gets a little sore, so perhaps some kind of plate to spread the load over a greater area is in order. I bet you could even put a couple of drops of H2O2 in the water to help oxygenation.
Just can’t get the seal properly near that water heating element :)
Gprent: I understand what you are saying about the complexity, but I like to explore as many loosely related fields as possible, and extrapolate that, and only then reduce the number of variables to the minimum needed, which usually ends with a very simple and elegant device. I wanted to do the same for a PE device, so this is just work in progress. Once reduced, if it looks viable then it might even get built.