Circles. Millions and millions and millions of circles. This type of issue isn't something that gets fixed in 1 or 2 or even 10 training sessions. It can take weeks or months of consistent work to get a horse like this to consistently level out and slow down...and even then, one little backpedal and you have to nearly start all over.
Since he's evading the bit and not responding to your cues to slow down, completely ditch the idea of using 2 reins on him. When he starts to get all excited and chargey, take one rein lightly and circle him in big circles until he wants to stop. Then, let him straighten out again and continue on. If he starts to speed up or his head pops up again, take him in circles the other way. Do NOT break gait at all until he's loped a few strides on a straightaway in a calm manner with his head level. THEN, I'd pick up 2 reins gently and ease him to a walk and let him walk until he's got his breath back. Then ask him for the canter again and start all over.
Even in the circles, if he gets to going too fast, only pick up your inside rein and spiral him down to control his speed. When he is going the speed you want, slowly spiral him out to the bigger circle
This is just about the most effective method I've found for dealing with a chargey horse. It takes a lot of work and it's very hard on the rider (you'll likely be puffing almost as bad as him and you may end up with cramps in your sides/hips), but it does work.
To start with, on this, I would take him out completely by himself. When he's doing good 100% of the time, then I would find a friend who is willing (and able) to go out with you. Then, start it all over again except when you take his head and start him on circles, have your friend work circles too (they don't have to lope, but it's better if they do). Slowly (and it will be slow, probably take months), build up to taking more and more people with you but always make sure that there is at least one willing to stick with you and play along when you have to circle.
All this is work toward teaching him to completely ignore what the other horses around him are doing and focus on you and what you're asking.
This is why I really like that my main schooling area is bordered on 2 sides by pastures with horses in them. If I can work a young horse and keep them focused on me and the circles when there are 10+ horses running and bucking and playing all around him, then I won't have a problem taking him out on a trail ride with multiple other riders. I can take him to an arena and warm him up without him trying to "race" the other horses, etc.
One other thing about a horse like this, it requires permanent vigilance. A horse learns best what they learn first and even after months of re-training to get him to lope out nicely with other horses around, even 1 instance of allowing him to get excitable and not correcting it can undo much of that training and make you have to start all over.
Last edited by smrobs; 08-11-2013 at 01:01 PM.