What do polite little 1-year old boys do?

They drink water from sippy cups. Kind of.

From Video: Gurgle, gurgle, hissssss.

Note: Please excuse the poor video quality. The video is actually very high-quality, but the file is so large that it gets all wonky when I upload it to the web album. So while you may not be able to see QUITE all of the water running down Linus's chin, you'll still get a pretty good idea.