"For a dog who loves to tear apart stuffed animals, make a durable activity ball with a Hol-ee rubber ball, scraps of fabric, and treats. When they pull all the fabric out, stuff it back in and start over :)"
Great reference photo - tying your rope halter knot correctly. When a rope halter is tied correctly, the knot will not slip if the horse pulls back, nor is it likely to become so tight that you can't untie it. When a rope halter is tied incorrectly, the knot will slip if the horse pulls back, allowing the horse to slip out of it, and after it has slipped for a while, it will tighten down so that you'll probably never get it untied.