First of all, "wet pumping" refers to the practice of vacuum pumping while the vacuum chamber is filled with enough water to keep all contained body parts submerged, and should not be confused with "hydraulic pumping", in which fluid is actually coursed through a pump. Vacuum pumps are designed to work only with gases, like air, and are not capable of carrying fluids. To wet pump, one partially fills the vacuum chamber (cylinder) with warm water (prior to connecting it to the vinyl hose coming from the vacuum pump), then mounts the cylinder and inverts the cylinder upwards so that the connection fitting is well above the water line, within an air space remaining at the top of the cylinder. Next, the cylinder is connected to the vinyl tubing and hand or electric pump and then begins vacuum pumping. While the choice is ultimately yours to make, 'wet-pumping' is not something which we would promote anyone doing, and in fact advise against this activity. Here's why: Wet-pumping, regardless of what you may hear elsewhere or see in forum discussions, etc. on the internet, has only one benefit; warm water 'feels good'. It does not speed up results, protect you from blistering, or provide any other so-called benefit claimed, except that being immersed in warm water feels good. More importantly, what it does do is increase your potential for injury. When wet-pumping, one over-saturates the outer layers of skin & tissue which normally provide protection to the tissues beneath. Much like the commercials for paper towels or toilet paper demonstrating the differences in strength between a dry sheet vs. wet, the wet-pumped skin/tissue lacks it's normal level of elasticity and strength, making it much easier for them to become torn or damaged.