A punch to the back of the head or neck. The punch is delivered during anal sex. The purpose of the donkey punch is to cause the recipient's anus to clench tightly on the puncher's penis, thereby enhancing the puncher's sexual gratification. See donkey blow
"Just as I was about to bust, I gave that bitch a donkey punch. I came so hard, I almost passed out."
by tony608 November 05, 2008