EndoTapping was developed by the French master horseman, J.P. Giacomini, as a way to initiate a state of relaxation in horses during handling and training. It involves rhythmic tapping of certain zones on the horse, which is believed to provide a rush of “feel good” or release of calming endorphins. The theory behind EndoTapping is that a horse can’t learn under stressful circumstances, when its sole focus is on survival. By using EndoTapping, you can circumvent the flight response, inducing a state of relaxation, leading to willingness.
At first, tapping on your horse to induce a relaxed response may seem like tree-hugger, woo-woo stuff, but when it comes time to trailer, vet and train you're going to want a horse that is relaxed and thinking. In addition, horses learn more completely when their bodies and minds are calmly focused and not running on adrenaline.
I'm just beginning to learn about and incorporate endotapping into my training and rehab. As I learn more I will share more! In the meantime, you can look up Charlotte Cannon, The Cannon Method.