this is my defintion or style of clamping.....I stroke until erect then use a cockring or thick rubber band around the base of my cock. I then stroke until I am rock hard, meanwhile I have a finger under the band allowing blood flow, then pull out the finger, trapping blood in your penis. do this several times, until your are really rock hard. I then slowly jelg to the end of my penis, a few of these and my head gets larger. do this for several minutes, several times, always let blood flow after a few minutes. results are slow and temporary, but over a few years, it becomes permanent. my penis head use to be narrow, pointed and slope up to my glans. it still looks the same more or less flaccid, but when I am hard, my head looks bulging. it's blunt and much more round and full, than it ever was.