Trust me none of these suggestions are inhumane, because safety is of the utmost for our part.
GO have a nail with any type head on it.
Place that nail with the head on the inner side of your hand between your index and middle fingers. This means the sharp end will be to the outer side of your hand. When your horse goes to bite your hand or where ever, bite back with the sharp end of the nail. I do not mean jab the horses nose with nail. Just let the nose connect with the nail.