If a toddler broke for the street, I swatted a butt.
A toddler played with an electric outlet, I smacked the paw that touched it.
Some things, like electrocution and being hit by a car, will result in pain. I preferred they got that idea from my hand, which was measured, rather than from an electric current or a car, which would have been much less temperate.
I didn't hit them for hitting each other. For that, they were exiled. Antisocial behavior earns removal from society.