Quoted from RobT:From what I've heard, the pictures of the injury to the child make it pretty obvious that this went well beyond a spanking or "whoopin". Especially since we are dealing with a 4 year old.
According to the urban dictionary, a whoopin can be administered using a switch, which is what AP allegedly used.
http://www.urbandictionary.com/define.php?term=WHOOPIN
Whatever you call it, if you're leaving marks, you're doing it wrong.