Take a look at the second definition here: http://www.urbandictionary.com/define.php?term=tongue%20in%20cheek The example provided there is pretty funny (and accurate). :)

Tongue-in-cheek is a phrase used as a figure of speech to imply that a statement or other production is humorously or otherwise not seriously intended, and it should not be taken at face value. In the past, it may also have indicated contempt, but that is no longer common. Since "tongue in cheek" means "with ironic or flippant intent," in your scenario, the use of the expression does not quite work. In Chinese, the expression is most closely translated as 讽刺 or 幽默. The expression does not mean "to pretend to do (something)". Examples of the use of the expression: The whole idea of government support of religion surely has to be tongue in cheek. (That is, because of the separation of church and state in the United States, the idea of government support of religion must surely be a joke). With tongue in cheek throughout, the author warns us of the pitfalls of high school. (That is, with flippant humor throughout, the author warns us of the pitfalls of high school.)