Hi there, I'm fairly new to pumping, and am having a problem because of my large mushroom head. As I pump, my head expands to touch the tube and block the vacuum before the base of my cock does. So my head gets much more suction than anything else and I pack at the top before the bottom (which seems to be the opposite of what I've seen on this site). There is some suction at the base, but not nearly as much as on my head. If I go up a tube size, I'm worried that I won't get any suction at the base and it won't help my length (which I'm interested in most). Anyone else have this issue? Thanks!