I road horses for many, many years competing in events and teaching others how to ride. TWICE I have been bitten in the midst of explaining something about horses to children.
The first time, I was facing the horses behind and bending over to demonstrate cleaning out a hoof. The horse turned and bit me right on the butt.
The second time, I was showing some campers how to pet a horse so he knows you're not a threat. The horse in the next stall reached over and took a bite out of a my shoulder. That one left a scar. I wound up having to turn to my campers and say, "And now I'll show you some basic first aid!" even though inside I was screaming.