I got this after much consideration to give pumping an honest try. I was disappointed that on the first use, and every use, the quick connect at the cylinder leaks so bad it will not perform suction. If I hold it in just the right position while pumping like crazy, I can get it to do the job. After achieving suction, the tube has a check valve in it to hold the negative pressure allowing pump and hose removal and even moving around the house with it staying in place! I recommend purchasing the tube seals (kit does not come with any) they are needed to isolate suction to the shaft and form a much better seal against the skin to hold the vacuum. I am happy to report that I have been able to add a little to my girth (maybe 1/8" wider) after just 4 days of use, and it seems to have increased sex drive and my abilty to cum more than once when with my partner. I would love to see an improvement on the connector, so it is does not have to be finessed to use - the leakage while the hose is attached is the only (however quite a large) problem with this unit. Happy pumping all who dare to venture, and thanks SheVibe!