I remember watching John Lyons work with a young horse at a symposium in San Antonio. He placed an old tire carcass on the ground and had the colt step in it with his front feet. When the colt got quiet, John moved his own leg backward along the colt’s side and bumped him softly. After a while the colt took a step away from John’s leg with only a back leg, because his front legs were confined by the tire.
Nowadays we don’t use the tire so much, although it might be a good idea on some colts. I recommend sitting slightly forward in the saddle, using the reins to keep The head, shoulders, and front legs in position, slide your leg on one side backward. Do not kick, but lightly squeeze, we want the position to mean something not the pressure. Now, as you were doing from the ground, tap just behind your leg with the stick. This already has meaning to the colt. Sooner or later he will step over with a hind leg. Reward him a with a rub of your hand. Now go to the other side. This “one step over, each way” begins the process. When it gets easy, take two steps. Then three. Sooner or later you will be able to turn him completely around without his front legs leaving their position. This is called a turn on the forehand, or indirect pirouette. You have established a communication with your horse that says “when I change my leg position backward, you move your haunches and back legs away from it.” This should be part of every day’s work, but only for a short period of time, not enough to give him or you sore muscles. I don’t mean to come across as the oracle. I’ve struggled with these training problems long enough that wish for others to have an easier path. I’m glad horse’s can’t talk, otherwise I’d have to hire the KGB to guard my string, lest they give you their version!