Try trimming any hairs around the seal also. If you are not getting a good seal you can pump forever and get nowhere. You should definitely feel it sucking you into the chamber. This will result in you getting hard while in there. Of course once you let off the vacuum you will resort to a huge flaccid as many are mentioning. I don't think you are getting a good seal by the way you said pump forever. I usually get 2 good pumps out of mine and then I'm at max pressure. I'm 6.75" BPEL and 4.5" EG. So I am nowhere near max size for my hercules pump.