Smacking an animal serves no purpose. They will only see you as a threat and like you less, aside from the fact that it's unbelievably stupid and cruel.
When my cat gets a bits feisty and starts "bite-playing", I'll just move away and say a stern "no!", then ignore her completely.
A couple of times, she actually had a hold on my hand with her claws, so I blew hard on her face, and she let go. Believe me, no cat likes that!
It would be like someones child getting home from school or after being out, coming over to give you a hug and a kiss and then you lamping them one!
I agree with BOO all you need to do do is push the dog away and sternly say NO!
i would never smack my dog. its not fair- all the animal can do to defend itself if you are hurting it is bite you & then it gets put down. also if an animal is used to getting smacked you will have a harder time calling it to you as it will associate your hands with smacking.
i have kind hands so my dog is never afraid of me & does not flinch or shy away from me.
if he is naughty i will say OI! or DONT! & he stops misbehaving as he knows i am serious. the consequence for ignoring this is being put out of the room & being excluded for a few minutes which he hates!