Using pressure and release to teach a horse to back up is a clear demonstration of how the principle works in practice — the handler applies a specific pressure cue, maintains it through wrong answers, releases it at the correct response, and repeats until the horse has learned that backing is the behavior that produces relief. The exercise is simple enough to be one of the first things taught to a young horse but nuanced enough that the quality of a trained horse's backup reveals a great deal about the quality of its pressure-and-release education.
The backup cue from the ground is typically applied through the lead rope — steady or rhythmically pulsing backward pressure toward the horse's chest, sometimes supplemented by a light touch on the chest or a gesture with the free hand. The horse's first response to backward pressure on the lead rope is usually to raise its head and brace its neck — the opposite of backing. The handler maintains the light contact through this wrong answer without escalating to a pull, and waits for any backward weight shift, which earns an immediate and complete release.
Over many repetitions — sometimes many in the first session, sometimes spread across several sessions — the horse learns that backward movement produces the release and begins to offer it more readily. The quality of the backup improves progressively: from one reluctant step to several smooth steps, from requiring firm contact to responding to a feather-light cue, from being crooked to being straight. Each improvement reflects a deeper understanding of and response to the pressure cue.
From the saddle, the same principle applies to the rein backup. Light contact through the reins suggests backward movement, and the instant the horse takes a step back, the contact releases. A horse with a good backup on the ground learns the ridden version significantly faster because the concept is not new — only the source of the pressure has changed.