When my dog Vito, a miniature schnauzer, comes in from outside and he either has muddy, wet, or snowy feet he knows to go and get in the bathtub to get them washed off. He automatically does without being told to do so. He waits until I come to wash them EVEN if it is in the middle of the night. He has a doggy door!
He rarely throws up, but the two times that he has, he also goes and gets in the tub to do it. He is a a very special dog.