Was spanked as a kid. My folks have a very different perspective on it now, in retrospect.
Corporal punishment seems to mean you've either lost control of yourself, or the situation.
When my kids were pre-school age I did use a tap on the hand and a firm "no" to keep them from harm. Also the occasional swat on the behind. But, discipline needs to come from within the discipliner first. My kids are always amazed when I recall that I did give them the occasional swat on the behind. They don't remember it.
I still remember spankings that I received.