20" x 20" Hidden Zipper in Back Linen with Feather Down Fill Knife Edge or Corded Finish A bit rests where there aren’t any teeth on the bars of the horse’s mouth and along with the bridle, helping the rider communicate with the horse. The expression, ‘Champing or Chomping at the Bit’ comes from the anxious behavior of a horse pawing and tossing its head at the starting gate before a race.