Title text: November marks the birthday of Charles Schulz, pioneer of tongue awareness.
This comic is a homage to Charles Schulz, the creator of the comic Peanuts, who was born on November 26, 1922. Here's the comic in question by Schulz. xkcd's version has Black Hat as Linus, and Cueball as Lucy. In both comics, when you start thinking about your tongue, you can't stop thinking about it. This is similar to the way that if you start thinking about your breathing, you stop breathing unless you consciously think to breathe.
This link also indicates that Schulz's comic is not completely about tongue awareness, instead has deeper meaning about one's existence in the world.
- [Black Hat and Cueball sit in a room]
- Black Hat: Did you know November is Tongue Awareness Month?
- [Cueball is suddenly aware of his tongue]
- [Cueball continues to be aware of his tongue]
- [Cueball is *still* aware of his tongue]
- Cueball: I hate you.
- Black Hat: Enjoy the next four weeks.