I have taken Viagra once just to see what it was like and I just got a hard-on that was like a solid piece of cement that I couldn't get much feeling out of....It was effective, but I lost sensitivity in my cock so I won't use it till I am forced to by nature, by that time something will be on the market that will be totally time controlled or install a button on the side of my body to where I can push it and it automatically releases the drugs into my blood stream like an insulin pump lol...