Have you tried holding a whip straight up ahead of him? I found out by accident that a neighbor's Arab mare had been trained for halter in just this fashion. Dead-headed, sleepy mare instantly came to life, parked out, flared her nostrils, and flagged her tail when I held the longe whip up ahead of her face to pick some poop off the handle. It was quite impressive.

"Gypsy gold does not chink and glitter, it gleams in the sunshine and neighs in the dark."