I personally think it confuses horses the way most people do it. They literally go toward the horse or ask it to do something then just stop and do it again. It's not exactly pressure and release. Horses learn through the power of association not random retreating.
Approaching is applying pressure, once your horse takes a small step toward your ultimate goal, release the pressure. Horses do not learn from the pressure itself -- they learn from the release of pressure. Then your horse should lick lips to show they understand what you are asking!