I got the figure of speech 'tongue-in-check' second time. It was difficult to grasp the usage of the tongue-in-check first time I read. The words in it is quite different than what it actually means. It is not too difficult either but it is not going inside me. Do you use tongue-in-check in your speaking or writing English.
Here is the meaning and usage of tongue-in-check with examples I collected from few places:
Tongue-in-check is used for statement not meant to be taken seriously. The facial expression typically indicates that one is joking or making a mental effort. It means cleverly amusing in tone as well. In chat or written text, tongue-in-check can be expressed using :P symbol.
I have noticed that names of stories are very tongue-in-check.