If you are spanking out of frustration and not for the sole purpose of grabbing the attention of a child that will not listen, then I'd consider that fairly abusive. The reason you spank is because 3 year olds are not going to sit down and talk rationally about what they've done when they're throwing an absolute tantrum. You do it to grab their attention, stop the fit, explain why they just got a spanking now that they're attentive and then you give them a hug, tell them you love them and how much you really don't like having to get their attention that way. Do it a few times, the right way, and the behavior that causes it should subside. The goal is to do it as least often as you possibly have to. No good parent enjoys spanking or resorts to it as the first solution. It should be the last solution.