Meaning of pin the tail on the donkey

pin' the tail' on the don'key

Pronunciation: [key]
  1. a children's party game in which a blindfolded player, holding a paper tail, is turned around several times before a large picture of a tailless donkey that the player then attempts to locate in order to pin the tail in place.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.