Abstract: A device for humanely controlling an animal's behavior while on a restraining device such as a leash by using the resistant force between animal and restraint to engage a trigger that activates release of a distracting or deterrent spray or gas, or a sound. The device is attached to the animal's body, with the triggering mechanism against the animal's skin. In its application as a means to train dogs to walk on a loose leash, the trigger may be situated inside a collar, such that triggering occurs when the dog pulls the leash taut. Triggering can also occur if the user pulls back on the leash to administer a correction. The trigger's springiness additionally provides shock-absorbing protection to the animal's neck. Embodiments with enhanced features, based on the same mechanical principle, are also described.