Proud owner of one Lunar acre! (Campanus Crater, The Moon)
Depends. You or the horse sucking on the bit?
If he's trying to swallow on not drool, and you have a KK, he might have too much saliva from the metals in the bit. Well, too much for him. Try something without copper or mixed metals and see what he does.
"Relinquish your whip!!"
DISCLAIMER: All sphincter knots are the responsibility of the reader.