What to do when my horse "dances"?

My TB gelding, 12 years old, will sometimes start to jig and jive or "dance". I call it a stupid little jog but, anyway, what do I do to stop it? The right way? I feel bad because when i pull back on my reins he doesn't stop, so i then give him a tug on his outside rein. He is usually still dancing at this point so then i give him a sharp jerk on the outside rein. I don't what to hurt him, but he dose quit. Is there a better more nicer and effective way to make him stop?