When something is described as “tongue in cheek,” it means that it should not be taken seriously. This type of humor is often wry, subtle, and sometimes difficult to catch, in contrast with more blatant forms of humor. In England in particular, such jokes, fiction, and films have been elevated to an art form, as this type of dry wit is especially valued in British culture.
This term appears to have originated in the 1800s, and it is a reference to the idea that one is pushing the tongue against the cheek to maintain a straight facial expression, or to prevent laughter that might give the joke away. Pressing the tongue against the side of the cheek can help to suppress a smile, and it also makes it hard to talk. People usually do not literally stick their tongues in their cheeks after saying such a joke, although they will sometimes explicitly state “tongue in cheek.”
Mastering the art of telling a joke with a straight face takes time. The idea behind tongue and cheek humor is that the joker wants people to take the joke seriously for a moment, until someone realizes the ludicrousness and points it out. In a mixed group, people who are in on the joke may help to perpetuate it, and while subtle jokes are not told with the intent to deceive, they are sometimes misinterpreted, resulting in confusion until the matter is straightened out.
Tongue in cheek humor may be ironic or facetious, or it may take the form of more obvious parody and comedy. Some filmmakers, for example, enjoy making films to lampoon the genres they work in. Horror movies, teen films, and action films are often ideally suited to such parodies, which can vary from the obvious to the subtle. Authors may also produce columns, poems, or books which are intended to be facetious, although some authors have ruffled feathers as a result of reader misunderstandings.
This type of humor is distinguished by its subtlety, rather than its flashiness. Some of the best only strikes people minutes or hours after the joke, and some people become known for their ironic senses of humor. Many people who engage in this type of humor also make fun of themselves in the process, with mildly self-deprecating humor that is sometimes designed to diffuse irritation among people who have trouble understanding less obvious humor.