What kind of bit is in this boy's mouth?
Disclaimer: I'm no trainer or professional, just a horse momma. :)
I just wanted to say-- if I had your horse and I was going to canter him, I would sit deep and give him a loose (soft) rein to say "go ahead, relax." I'd ride out what he gave me with the deepest seat I could manage, even if that meant grabbing the cantle to keep my butt in the saddle and taking deep breaths. I'd bring him under control with my seat, not the reins.
That being said, I agree with everyone else about waiting to canter. I think that you need to have better seat control of his trot (slow it or speed it up with only your seat and leg) and more relaxation before you can get him moving through a canter the way you'd like.
I see a few things in this video: a few yanking competitions-- you apply pressure, he throws his head up, you apply more pressure to bring it down, he throws his head... and also, a horse who is very sensitive to your posture. You'll note that the "nicest" canter moments were when you sat deep, and every time that you leaned forward (even an inch!) he fell apart and ran away with you, so-to-speak.
Teaching a horse to accept contact is largely a matter of trust--the horse's trust that your hands are steady, for one. I am only getting to consistent long-and-low & contact after 3 months of riding my gelding. Before that, I practiced getting his gaits to be consistent and relaxed on a soft rein, and lots of seat control! Not saying that this is right (I'm no trainer!) but you're in your horse's mouth the whole ride. Every time I get on my horse, I make it my goal to talk more through my legs and seat than with my hands.
I hope this helps! :) He does look like a sweet boy. Just talk more with a trainer about how to help him relax and how to help you sit secure.
Last edited by existentialpony; 03-04-2013 at 04:52 PM.