Originally Posted by SpiritJordanRivers
He doesn't know how to canter on the lungeline yet.
If your horse doesn't know how to canter when asked on the longe line, how do you expect him to know how to do it undersaddle, be it slow or fast? IMO, he needs to learn the vocal command "canter" while on the line, and then you need to ask a buddy to longe him while you sit and cue from the saddle, and only when he consistently performs on the longe line ask him to do it by himself. Having a friend hold the line while you sit on him helps him learn how to balance at that speed carrying a rider, and neither of you need to worry about establishing a bend or steering, because the circle does that for you. I think that he lacks consistency because he's not totally sure how to balance himself at that gait. A horse naturally canters across a pasture - no horse ever would naturally carry a 100 lb plus rider at ANY speed. Be patient, and go back to longe work. Also, if you do continue to canter him undersaddle, any time he takes off with you, I would do tight trotting circles, then ask him again. After some repetition doing that, he'll learn that slow and controlled means last work than fast and crazy. Alternatively, just let him tire himself out, and then ask for some change in directions, or multiple walk/canter transitions, then reward him immensely and get off. End on a good note, and lots of repetition. Good luck!