Whenever I move something, anything, towards Lilli's mouth, she opens it very obligingly wide. This comes in very handy when I'm trying to get her to eat or drink. (Sometimes when I have a spoon (which she recognizes) she'll open her mouth wide even before I move it towards her mouth). But it's kind of gross when the dog sniffs her mouth and she opens her mouth as if to say "ok, put your nose in here, if you want!"