One of Ella's favorite liberty maneuvers is the back up from behind! I just tap her, say "back," and she backs towards me!
***She has never turned her butt towards me in an aggressive way. If you teach this, make sure that you are experienced enough to get after your horse if they ever get pushy with it or back towards you without asking. That can become very dangerous.***
I taught Ella this liberty back up last year. She really picked it up fast! It only took her about five minutes to learn it! I have only worked on it here and there though, because I don't want her over-anticipating it too much in our sessions.
Teaching the back up from behind:
Ella already had a very soft back up with pressure on the halter, which is step one! (If a horse won't back lightly to pressure, go back to the basics.) I added a second lead rope for "reins," similar to if I was ground driving her. I asked her to back up a few times with me behind her, just saying "back" and adding slight pressure. Next, I added the whip. I lightly tapped her, said "back," and added pressure on the halter. She started to associate the back up with only the tapping and saying "back." I took off the halter and lead ropes and ta da! The first time I asked her to back towards me at liberty she nailed it! She got a treat and lots of scratches and we called it a day!