I have and it is great! The secret to pumping is starting with a rock hard cock and viagra gets you there faster and keeps you there longer. I find the results to be superior to not using it. I also find that the sensation is out of this world! I have to be very still when my dick is in the tube as I can just bust a wad from the pressure alone. It is also great after you come out of the session because my cock is so beautifully shaped and defined and I can fuck and fuck and fuck for hours!