Great thread, Wadzilla!
Agree. I had the same thougth before reading this thread, and now it is reinforced; doing clamping we force the tunica.
Now, repeating 2-3 times this work (clamping) we are pushing the tunica to the extreme of it’s elasticity, near the point of deformation; at this moment the tunica should be at it’s weakest point, so stretching will put deformation in vertical direction, and not only in horizontal one.
Hope what I’m pointing is clear.
Pumping could work that way as well.