Answer: Snot Bubbles

Remember that time when you fell asleep and blissfully blew massive snot bubbles out of your nose while slumbering away? No? Well then, clearly you’re not a sleepy anime character. The whole slumbering-snot-bubble bit is a particular trope you’ll rarely, if ever, see in Western animation, but appears quite often in Japanese animation.

The image seen here, captured from an episode of Pokémon, is a perfect illustration, if you’ll pardon the pun, of the phenomenon where sleep is indicated not by floating “Zzzz”s (as it often is in Western animation), but by a rhythmically inflating and deflating bubble. Although seen as gross by Western viewers, the representation is perceived as cute by Japanese viewers.