On the next spectrum of the level from the body language of licking lips is the nervous tick or action.
It may be the pressure of a tough question or an uncomfortable situation or room that would cause one to change their behavior and display.
If you spend some time watching the television show “Cops” you will see the suspects start licking their lips after a few tough questions are asked with long pauses or short pauses.
Are the suspects lying before or after they lick their lips?
Quite possibly but this show is a good place to look and watch for the signs and signals of lying.
If you are a woman / girl and ask a guy do you love me?
You ask your boyfriend where he was and all of the sudden all of his body language changes into something not normal. Could this be a sign and signal that your boyfriend is lying or did he really go to the new bar?
You go to a new bar and you look over in the corner and notice this girl who winks at you and slowly starts licking her lips.
This rush of energy has to go somewhere for them and the lips are the answer.
You would see this as a common trait or action that happens.