How do you teach a heel horse to stay straight in the stop?

A heel horse that stops crooked — swinging its hindquarters left or right rather than driving them straight under its body — puts the rope at a bad angle, makes the dally harder, and over time creates uneven physical stress on joints that absorbs thousands of stops throughout the horse's career. Straightness in the stop is not corrected at the moment of the stop itself but installed through straightness work throughout the horse's general training. A horse that travels straight, responds to both legs independently, and can be aligned with minimal rein input at all gaits will carry that straightness into the stop far more reliably than a horse whose basic straightness has never been confirmed. In the stop specifically, crookedness almost always falls to one side consistently — the horse that swings its hip left in every stop has a pattern rooted either in a physical asymmetry, a one-sided stiffness, or a habit of drifting to that side that has never been corrected. Identify which way the horse drifts and use the opposite leg at the moment of the stop to hold the hindquarters straight — if the hip swings left, the left leg holds it right at the instant of the stop cue. This correction must be applied at the beginning of the stop, not after the horse has already drifted, since a drift corrected mid-stop produces a wiggling, stuttering stop rather than a straight one. Frequent straight-line stops in flat work, with deliberate attention to hip alignment, build the muscle memory and body awareness the horse needs to stop square automatically. Crooked stops that are never corrected become crooked stops that never improve.