S'en tamponner le coquillard

Literally: To dab one's coquillard with it

Example: “Tu peux critiquer ma coiffure, je m'en tamponne le coquillard.” — You can criticize my haircut; I don't give a hoot.

English equivalent: Not to give a hoot

Origin: A vulgarity in polite dress. Se tamponner le coquillard is cited by Aristide Bruant in 1901, and coquillard itself has never been fully explained: Alain Rey derives it from the vulgar senses of coquille (shell), 16th-century slang for the female genitals, while others read coquillard as slang for the eye and tamponner as simply to strike, as in autos tamponneuses (bumper cars). That second reading ties it to the older alternative, s'en battre l'œil (to beat one's eye over it), in use since the 17th century and found in La Fontaine, where œil is coarse slang for the anus, the same softening as in mon œil ! (my eye!). The phrase attracted a tradition of absurd elaboration about what one strikes with: a rabbit's paw, a lobster's shin, a mammoth's tail, even a breaded beetle leg. The bluntest member of the family, s'en battre les couilles (to beat one's balls over it), means exactly the same and is probably the most common in everyday speech; young people clip it to balec (also spelled balek), from bats les couilles.