Originally Posted by Prinella
Another option is rather than tying him to begin with simply pass the rope through the twine have a gentle hold of the other end. If he gets worried feed a little more rope through but be prepared to met with gentle pressure if he begins to pull slightly keep pressure momentarily then feed more rope and give a release. Most times the horse will pull back hit pressure and then panic, if there is a release from that pressure you avoid the panic and don't teach them to pull.
This is what I suggest ... I went on a ride yesterday and we had 4 horses - before we'd had them tied for 5 minutes, 2 horses broke their leads. I knew Spot was afraid of fly spray and got antsy when you went to saddle him, so I untied the knot and fed the rope through but held on to the end that wasn't attached to him. That way when he pulled back, I could give him enough slack to where he didn't pull and break something. In situations like that when you're in public and can't risk a broken snap, that method is best. Now when you're actually working the horse, I would use the same approach, but in a different way:
Take a long line, like a lunge rope or something similar, and grab a buggy whip, and use something solid (like the big rings on the trailer or a hefty hitching post) to feed the rope through/around. Hold the excess in one hand and the whip in the other, and stand back a bit. Every now and then, put a bit of pressure on the rope so that the horse feels the pressure on his poll (typically what induces a lay-back). If the horse lays back, push him forward with the buggy whip. As soon as he jumps forward, take all the pressure off. It worked for my TB gelding that would lay back when he was tied alone.