[1] https://fr.wiktionary.org/wiki/s%E2%80%99en_badigeonner_les_...

It exists as an entry in the https://fr.m.wiktionary.org/wiki/s%E2%80%99en_badigeonner_le... but I don't think I ever heard someone uses it. The non vulgar original version seems to be "s'en brosser le nombril avec le pinceau de l'indifférence" (To brush one navel with the brush of indifference) and found it's origin in the comic strip Achille Talon.

My own personal favorite would be (it's very inelegantly translated) it touches one [of my testicles] without making the other move (maybe invented by former president Chirac, at least made popular by him). It's well known and understood and has the advantage to be vulgar enough without actually making an explicit reference to testicles.

Isn’t this quite long if you don’t care?

Although these swears seem extremely mild, they are actually quite heavy in Québec, even though no one goes to church anymore, because of how dominant the Catholic Church was until the sixties. They would be censored on TV, for example.

German "das ist mir Wurst" is also a lot weaker than "zero fucks given", at least use something stronger like "das interessiert keinen Arsch" (no asshole cares). Also "zero fucks given" in the sense of "irresponsible, he just does it and doesn't care who gets hurt" doesn't really have an equivalent idiom. Maybe "als druff" (just go full power straight ahead) or something.

But none of them is an exact match as there's no perfect overlap for all situations to which "zero fucks given" can be applied. Which isn't too surprising as most idioms and even most words don't map 1-to-1 between languages even when they share a common root.

No (female) pig cares about it / No sow cares about it

Also, "I slap my balls on it" is probably the translation of "je m'en bats les coulles", but a better translation would be "I slap my balls with it".

It is sometimes shortened as "j'm'en balec" or even just "balec".

One I heard in the army is “je m’en tamponne le coquillard avec une patte d’alligator femelle”. “I pat my butt with a female alligator’s leg”

In fact when you search google for “je m’en tamponne le coquillard avec”, google will autocomplete with “a lobster’s tibia”, “a morrocan shoe”, etc.

Never heard it either.

Why talk when you can physically convey the idea. I must say that this discussion makes me somewhat uncomfortable with the centrality of not caring in my culture.