Do it the old fashioned way, just attach your penis firmly to a string then attach that string to a doorknob... Get your friend to slam the door repeatedly until you can see the effects. It also works for testicle enlargement, but don't take my word for it! Go out and try it today
On a more serious note: If it's really gonna make you feel any better, go ahead. But personally, I don't really see the point in doing that kinda shit to your body.. Then again, my penis isn't 4" long 1" girth..