Tongue in cheek 

The actual act of a person pressing there tongue against the inside of there mouth, causing a bulge on the outside of there cheek for others to see. This is a way of telling another person to fuck off without saying it. The person that is receiving this insult has done or said something that the other person performing the act has found to be, upsetting to them or unable to deal with. There's also a probable chance that the receiver might not even notice or be aware the other persons is performing the action.(right over there head so to say) Those who feel superior to others, hiding a shame or a fear of insecurity, might use this action. Might even be referred to as a childish reaction to a situation that they feel powerless over due to the environment and or circumstances.

office setting

person says "the truth is that college educated people are a dime a dozen these days and theirs no real guarantee that you wouldn't be laid off"

receiver of the above statement performs the tongue in cheek action.

Tongue in cheek by Generic John January 23, 2009