Take your stick or whatever it is you're using and drive the front end away. Hit the horse toward the top part of his neck 6" or so back from the head. Start off with a tap and keep tapping him,slightly harder and slightly harder, till he gives that first tiny hint of moving away, and then stop with the stick or whatever. Point the direction you want him to go, and tap with the other hand. And yes, you might have to hit slightly harder each time, before the horse to realize he needs to move. I'm not saying hitting abuse type hitting. Just hard enough to get the job done. He'll catch on quicker when you release the pressure (stop tapping) after he gives the try. Just remember to point, and stop tapping when he does the right thing, no matter how small the try. Start small and work your way up. You may even have to tap his jowl area a few times to get that head going the right way. Once he understands what it is you want him to do, he'll be on his way. Then you'll have to do the other side. It might be easier, it might be just as tough to get him moving. Be patient, remain calm, and reward the smallest of tries.