To be quite clear I have never slapped my DC. I was physically punished as a child and I always swore I would never be violent in any way to my children.
I only ask because DS has been playing up mightily just before bed for the past couple of nights - running around, refusing to go to bed and generally being an all round nightmare. It takes about half an hour to negotiate him into bed with various threats of withdrawal of tv, toys etc and just occasionally I have thought a slap would put an end to this sharpish - I never would but I can sometimes see why people might be tempted.