Well, it takes a few weeks and the more often you train the quicker it is, with horses over about 6 you might need to do a refresher every now and then.

In my experience it's better to use a block and get on easily than to use your thigh muscles and end up hopping and hopping and put the horse off being mounted forever. The whole premise of horse-riding works because the horse moves away from the leg. He does this because somewhere deep in his mind he knows if something is gripping his belly it's a predator (ever seen lion hunt zebra) and he should run. Obviously with domesticity and training horses learn to curb the full-on flight reaction, but it is this premise which allows us to teach them so easily to move away from the leg, and mounting that is anything but easy and smooth for both horse and rider tends to incite this memory of predation and incites worry/panic (depending on the horse). If you're on already when he feels you mount he's ready to hear the next request, if you're trying to mount you become the lion-without-a-good-grip and stepping away from the "fuss" is a natural reaction. If you have to mount from the ground is there anyone who can give you a leg up?

Anyway, teching him to stand... THis worked on an arab stallion who was well past training age and downright dangerous when he chose to be. I started by grooming him from my mounting block. If it helps you can begin with him tied as usual and the block just next to him, then progress to standing in open space with the block next to his belly as it would be to mount. I used his bridle at first for better control but progressed to a headcollar and then nothing, just voice commands.

So you climb onto the block (or a chair - whatever it is make sure it is safe for you both- i found those large round plastic water-tubs, which have gently flared sides are good - stand it upside down and it has a biggish bottom for you to stand on and a wider base for stability) and say "stand" then begin to groom him. Whenever he fidgets you stop grooming and give the command again "Stand" and as soon as he's still say "good boy" and simultaneously go on grooming. Grooming the neck and withers is very bonding for horses so it's a good area to work on, be firm but gentle, scratch and pet him too. I tended to keep up a running commentary in a soothing voice "gooooood, there's the boy, there's the man, easy now" etc. while he is still and immediately be quiet and say only firmly and a little louder (don't shout or growl though obviously! lol) "Stand" if he moved. The idea is to get him thinking that standing next to that mounting block is the loveliest idea and he'll have a happy time.

Once he'll stand to be groomed, tack him up from it too. Lots of horses are eager to be off so the aim here is to let him see it's ok to be calm and that we don't have to get too wound up about going out for a ride. Once he's tacked up you stand on that block and chat to him and groom his withers and neck and keep asking him to stand if he fidgets.

Once he'll stand fully tacked up, relaxed and easy and not move you progress to putting your foot in the stirrup. Don't get on, just put a little weight there in the stirrup and wait. If he fidgets say "Stand" - you might find he takes a leap backwards in training and you need to recap the tacking up phase but it's worth it because it reassures them that what they thought to be true was in fact true. It's nice to stand still next to the mounting block.

Once he'll stand with some of your weight in the stirrup you can progress to getting on. Repeat "stand" as you settle and find your other stirrup, sit for a moment, then get off again. Do this a few times, each time giving lots of petting and scratching and "good boys" when he is still.

Eventually he will be standing still all the time you use the word "stand", and if he's fidgety the command will remind him to relax and wait.

Horses need reassurance that you know what you're doing. In the wild a lead mare makes all the decisions about who goes where and the pecking order and the stallion fights off all the competitors and protects them from unwanted attention. That means mares need to be dominated a bit (NOT whipped or shouted at, just dealt with firmly) and boys, even geldings, need to be treated with consistency and not fought with - stallions especially pick fights - outwit, don't battle - he weighs a quarter of a ton and he'll WIN! In all of this your aim is to make even better friends with him and teach him that it is the most positive and favourable option is to stand when you tell him to. Lead mares tell the others where they can graze just by looking at them, authority is confidence and confidence need only be projected, not felt (in case you don't always feel it).

Don't overdo the training sessions' length - 3 5-minute sessions will have a far more positive effect than one 15 minute one. Try to stop before boredom/frustration sets in on either side (you'll get to know the signs) and always end on the best note possible - if he was standing for 30 seconds at a time and it's turned into 10 then say stand, wait 8 seconds and then praise praise praise and end the session. Even if he is tied up to begin with, give him masses of praise for standing still.

HTH and it works for you. I take it you're flooded in? I hope that resolves soon.

Bx