It literally translates to "You're making the face", referring to the expression someone makes when they are upset or pouting.
Here are some examples of how you might use it:
* "Qu'est-ce qui ne va pas ? Tu fais la tête ?" (What's wrong? Are you sulking?)
* "Arrête de faire la tête, on va aller au cinéma !" (Stop sulking, we're going to the movies!)
* "Je ne comprends pas pourquoi tu fais la tête. J'ai juste dit la vérité." (I don't understand why you're giving me the silent treatment. I just told the truth.)