A tongue jut is thought to have evolutionary origins as a food rejection mechanism. We stick our tongues out to show distaste – either for others or even for what we’ve said ourselves.
Pushing the tongue through compressed lips is used to signal a cheeky attitude when done amongst friends, but has a more sinister meaning when done in competitive situations. “Tongue-jutting” is used in this case when people think they have gotten away with something, or have been caught doing something they shouldn’t have. However, in this case the tongue usually is pushed through the teeth and doesn’t touch the lips.
The gesture will be seen at the conclusion of an episode such as signing a contract or winning a hand at poker by bluffing. Most of the time tongue protrusion happens when people feel they haven’t been caught, but sometimes it’s actually because they’ve been caught. The statement reads “I’ve gotten away with this”, “I’m telling a cheeky joke or making a cheeky statement”, “I’ve made a mistake” or “I’ve been caught trying to pull a fast one.” Tongue through the lips or teeth can happen any place at anytime but signals the same thing almost everywhere and that is that a person is doing something that is pushing the envelop of acceptability or has gotten caught doing something that is unacceptable. Obviously if we notice this tongue language we should review what has been said and suspect highly that we’ve been fooled, cheated, that we or someone around us has been made the butt of a joke, or that the tongue protruder has realized they’ve made a mistake.