Tried some water pumping the otherday for around 20 mins split into two 10 min sessions. Was in the bath and got the tube halfway full [12 inch tube] and pumped while constricted with some string, tied in a loop knot. I noticed that I could handle ALLOT more pressure and I DID NOT get the soreness and irretible feeling when going longer in the tube at higher pressure ... didnt get much fluid, infact it was minimum, yet a great pump ... me thinks water pumping has GREAT potential .. the heat must also do the penis allot of good ... circulation being one of them.