A.K.A. A man's wedding band
These are usually placed on a man that for some reason feels that he would like to have his freedom takin from him.
Dustin: "Hey Jon, you want to go out with us tonight?"
Jon: "Naw man, I can't!" (Holding up his left hand)
Dustin: "Aw, I see! The Ring of Death
has taken control and got you by your balls!"