To spank s.o. (with a stick or hand); (for s.t. flexible) to strike or slap against s.t. else (as a jellyfish stinging s.o.); to strike s.t. against s.t. [-an].
If you don't obey, I'll spank you.
Don't allow that fish's tail to just slap back and forth.
Strike that rag against a rock so that the dust will leave it.
He almost fainted from being stung by a jellyfish.