Staying on the horse. help?

Ive been riding every saturday and sunday now all summer for about 8 hours a day (we do trail work and rides, but we also take breaks in between) on the rides we have a chance to canter and I found out that im very sloppy at this when im riding a different horse than my normal one. I tend to twist to the right and my right leg ends up going behind. I ride western btw. I know that I should be able to canter just fine being that I've ridden so much but I just can't get the knack for it. Also when we're cantering in a group my horse tries to pass the lead horse and my trainer says to sit on your pockets and to slow your horse down with your butt rather than pulling on the reins constantly. I find this alittle difficult to do and I still rely on using the reins to stop him and Im afraid that he will become hard mouthed. Please help! (I am using a tom-thumb bit btw)
Thanks!

I will mention that part of the shifting and swinging leg issue may be due to how the horse moves, though I likely couldn't say for sure unless I rode him myself or watched you ride him. I have one horse that does that to me regardless of how I try to sit his lope, he always flings me off to the right and makes my left leg slip way back. It is a genuine workout to keep proper position on him and it is done simply by pure strength. He's the only horse I've ever ridden (in 25 years of riding countless horses) that does this to me. Do other folks have the same problem with this horse or is it just you?

As for sitting on the pockets, that just takes time and practice to be able to do efficiently. Can you control his speed at the walk and trot by doing the same thing? It's easier to start slower and work on your own motion until you've got it down before trying anything faster. If you can't slow his trot by sitting deeper, then you aren't going to have much luck at the canter either.

I don't know how you're currently riding, but regardless of what speed the horse is going, try to avoid just using constant pressure on the bit to keep his speed under control. Have him go on a loose rein and if he starts speeding up, then only pick up the reins until he's going that slow speed again, then let the reins go loose. If he gets really bad about it, every time he starts to speed up, have him break down to a trot or a walk or, even better, stop him and back him up a couple of steps before going on.

As for the bit, well, I would change it in a heartbeat if he was mine, but you likely don't have any control over what bit you use, do you?

Maybe, I don't really have that problem on the other horse I regularlly ride, although I do bounce, but I've been working on moving my hips with him. The new horse however, tends to drag or keep his feet low to the ground while cantering so you have to shout at him to pick his feet up. Many people ride him and what my trainer says is that apparently other people ride on him just fine, so I assume its me.

As for slowing him down in the walk or trot it seems to work a little but I still have to use them bit some. And he goes on a fairly short rein but with no contact of the mouth. He is a more advanced horse than what im used to and actually goes somewhere when told. He has dicipline issues too.

Yeah I've been trying that but he tosses his head, maybe its because im bouncing? Im so afraid that he'll become hard-mouthed. Would it help if I tried take and releasing when trotting and cantering?

And no, I can't change bits unfortunately :/

Thanks for your help

Unfortunately, tossing the head is a pretty common problem with a tom thumb bit. The most you can really do is to try to make sure you're not being too quick with your hands. It's difficult, especially at the faster gaits, but the buildup of pressure on the bit should be gradual and steady so that the horse can respond to the lower pressure before he gets to the point of discomfort. If a person is quick or abrupt with their hands, then the pressure goes from 0 to 60 in an instant and doesn't give the horse time to respond before he gets jammed...so that can also cause head-slinging.

You can only do what you can do and, not to speak poorly of the place where you're riding, but it sounds to me like he doesn't have real great training to speak of to begin with and what training he does have doesn't match up with your riding level (soo many people get stuck in just that situation). Couple that with lots of folks riding him and you're bound to have issues with him.

Best advice I can really offer beside that is just keep plugging away and try to learn from every thing you do and how he reacts to those things. Focus on what your body is doing and how it affects what his body does.

Oh, and don't worry too much. With so many people riding him, I seriously doubt that you will be the one to give him a hard mouth...if he even ends up with one. Try to relax, as that will help you sit better and help him to relax as well.

I can offer a bit of advice for the cantering: sit deep, follow the horses movement (supple hips!), heels deep down, and lean back slightly. And try not to squeeze with your legs! These are all things I had to remember when I first started cantering.

I just say practice makes perfect !

I had a mini lesson with my lease owner and one thing she told me when we were trying to break from a canter to a trot without using any rein, was to stop moving with the horse. Stiffen those hips and kinda squeeze your glutes and sit deep. The reverse goes for having a horse move to a faster gait. Want faster? Move your hips faster. Want an easy pace? Move your hips at an easy pace.

It is a bit tricky [I know from experience] but once you get that click, its so much easier.

From a canter to a trot, I find that the butt squeeze method is a lot easier than a trot to a walk, because the transition [I find] is just so much bumpier.

Thanks guys for your advice! I tried it today and it worked very well! I sar as deep as I could, rolled my knees forward and tried to stop the horse with my body instead of the reins and it worked well! And when we cantered I relaxed, moved my hips with him and if I lost balance I grabbled the cantle verus the horn and it was amazing! My horse collected himself and slowed to a smoother canter because he didnt have to balance me so much. One thing though, my inner thigh area cramps up sometimes and is tight,.is that normal?

You will feel some muscle soreness. I particularly feel sore after I use a lot of leg and seat work, and I'm still recovering [yet exacerbating because I won't give myself a week off from riding/work to rest >D]. You might even feel soreness in your glutes.