The tea party (joke)?

A man is caring for his young daughter while his wife is at work. An hour or so before the wife gets home, the little girl asks her daddy if he wants to have a tea party. He agrees, and the young girl toddles off. A few minutes later she comes back with a small plastic tea cup full of water, and hands it to her daddy. He drinks it, the little girl giggles, and toddles away, returning again in a few moments with more water, which the man drinks. This continues for about half an hour. The man calls his wife, telling her that she just has to come see how cute this is, what their daughter is doing. So when she gets home, she watches her daughter toddle back and forth with the little cup once or twice. Her husband says, "See, isn't she just adorable?" His wife looks at him and, smiling, says, "There is only one place low enough for her to get that water from, you know."