I do not drive the horse. My job is to walk beside her during the wedding while she pulls the cart. My problem is that she gets really upset anticipating the bride to get into the cart. She was very close to rearing up and taking off at one of the weddings we did. She does not intimidate me by any means, but I was hoping I could get advice on calming her while people get in the cart. Her owner only wants me to jerk the halter under her bridle or put my arms up and say whoa if she gets rowdy.