Please refill my cup

I'm not quite how this ever started, but the kids each take a sippy cup to bed with them. Usually their sippies contain chocolate milk ... it is pretty much a staple around here. Several months ago, Mason began placing his empty cup in his doorway every night after he had drank the entire thing. This is his way of saying, "Yo ... mom and dad ... please refill my cup!" It cracks me up every time!