There are two issues, moving the horse and yielding space to the whip. If you want the horse to move in the first place simply bend the horse slightly and then touch with the whip. By bending the horse, and then touching it will move its quarters because it will be caused to loose balance. The other thing is to touch/vibrate (quick/faster)/or twack (touching where the rider's leg will be) until the horse moves, immediately remove pressure (the touches). Rinse, repeat. They learn very quickly (and that is associative to touches for supporting the leg when ridden). A horse should NEVER threaten, pin ears, etc, that shows you are being unclear and annoying (which often happens following an unclear application of any method, esp with a mare). Horses do not really ever test a human, they simply are higher or lower in a herd based upon training, clarity, respect; it is we who have to be clear w/o being crude. Ideally you have a live horseman who has trained horses before showing you how to use actions and not just an article.