I've got this stallion, he's six years old and he is an AMAZING horse, don't get me wrong, he used to buck alot, but I've gotten him to stop that. But now, whenever he gets frustrated he rears. Every ride I go on, he rears at least 8 to 9 times through out the whole thing, I don't really know what to do about it. I've tried tie downs, and some how he manages to rear despite of a tie down..
Rearing is very dangerous behavior in a riding horse. We must teach our horse to bend and flex to prevent him from ever rearing in the first place.
Before going out your next trail ride, outfit your stallion in a snaffle bit and teach him to drop his head and bend around your inside leg. Begin by riding him forward at the walk, you will need to ride with two hands as neck-reining will not work for this exercise. Turn him first to the left, apply light leg pressure with your left leg and focus yourself in the direction that you want him to go. Hold firm pressure on your left rein and light pressure on the right rein to keep him from turning on his haunches. Keep driving him forward in a circle until he drops his head and walks slowly, bending around your leg. Repeat the exercise on the right. By teaching him to first drop his head at the walk, he will be more willing at any gait. Repeat this exercise until each time that you bend him, he willingly drops his head and relaxes. When he gets really good at walking and bending and dropping his head, teach him to bend and drop his head at a stand still. Do this by taking slack out of both reins, slightly bending his neck (in either direction), and holding firm pressure until he drops his head a few inches, remember to reward him by instantly releasing pressure on the reins. If he gets confused and thinks that you want him to back up, say "whoa" and bump him gently with your legs. A horse with a good "head-down" cue physically cannot rear. They must have their head up in order to raise their front end off of the ground.
Contrary to popular belief, a tie-down will not prevent a horse from rearing and more times than not cause a horse to flip himself over on top of his rider. A training fork (or running martingale) is a much better tool when trying to teach a horse to keep his head in the correct position, as it instantly rewards the horse with release when his head is properly positioned.
Thank You and Happy Trails!