How do I get a horse to nod yes?

Hold a treat in one hand and a pointy object such as a screw or nail in the other hand. Show the horse the treat and then with the hand that is holding the treat make a fist and and flex your wrist up and down as if your wrist is nodding yes. At the same time gently press the point of your sharp object to the horses chest. Slowly apply pressure till your horse makes an attempt to bend his head down towards the pointy object. At that time give your horse the treat. How this works is the pointy object acts like a bug biting him and so he then attempts to shoe it away. Repeat this several times a day and in no time your horse will learn to nod just by seeing you flex your wrist.