My guess is the
horse wonders what the idiot on his back is doing when that happens and the
rider will be luck if the horse doesn't panic further.
I've had a
couple of rearing horses in my life. The first was 35 years ago, and there
weren't many books or horse gurus at that time to refer to and I only knew a
couple of cowboy trainers. I used the "milk carton of warm water on the head"
tecnique many times with that mare. Never worked, she pretty much totally
ignored it. Funny....I can't seem to remember how I got rid of that horse.
The 2nd one was
5 years ago, my mustang mare. We worked it out with one-rein stops and
continuing to ask her to go forward. After that, she was a great trail
companion.