Horses move when being mounted either because they are unbalanced, in pain or being ridden has not been a good experience for them. As with most behavioural problems, check that all your tack fits your horse properly, that his teeth are healthy and he has no areas of pain in his body. Then follow these steps:
1. Use a mounting block. Mounting from the ground torques the saddle and makes it more difficult for your horse to balance while you mount.
2. Teach your horse to stand square so that he is balanced and won’t need to shift his weight as you mount.
3. If your horse steps sideways or turns towards you, create a boundary on the opposite side by placing your mounting block close to a fence or wall or place poles on the ground to create a chute.
4. Ask him to bend around you by stroking just behind the girth so that his barrel is moved slightly away from you and his nose is tipped slightly towards you. Pulling his nose in too far puts him off balance.
5. Take up enough contact on both reins so that if your horse moves forward, you can put a block on the reins.
6. If he backs up, check how much tension you have on your reins, as that may be the cause of him backing up. Then tap his flank to ask him to move forward.
7. If he barges forward, move him around the mounting block until he’s back where he started.
8. Put your foot in the stirrup making sure your toe points forwards slightly – not pushing into your horse’s barrel. If your horse stands quietly, put some weight in your stirrup.
9. Push yourself straight up as if you are stepping up on a ladder – keep your upper body tall so that you don’t collapse on your horse’s back. Swing your right leg up and over your horse and gently lower yourself into the saddle.
At each step, praise him with a soft voice and a scratch on the withers when he stands still for several seconds. End the session at any point where you feel you have made progress.