I am trying to teach Zum to lower his head. If he ever stepped on his reins, I want to have a safeguard in place to prevent Zum from jerking his head up and breaking his reins or hurting his mouth. I pull down on one rein. I use more pressure on the rein to ask him to lower his head then when I ask him to turn his head. It is one smooth downward pull to the side. When Zum lowers his head, I release the rein as reward. After many repetitions, he learns to lower his head to pressure.