When Zum begins to toss his head, I quickly pick up one rein and stabilize my hand so he can’t move it. I hold the rein steady while he continues to flip his head around. The moment he quits tossing his head, I release the rein and pet him. He is learning that every time he flings his head, I pick up on one rein and hold his head to the side. Zum doesn’t have a clue what I am asking him until I ask thousands of times with the same reward.