Not as obviously cool as the above, but I always liked the way Tagalog (Philippines) works: wala akong pakialam. Literally translated, it's just "I don't care," but there's a layer of passive-aggressiveness that can make it really offensive.

To break it down: "wala" (Nothing, don't have) "ako(ng)" (I, me), "paki-" (polite request), "-alam" (to know).

Basically, that construction throws out the entire culture of politeness while blatantly saying you don't want anything to do with knowing about whatever that is. In many contexts, it's more offensive than swearing at the person.

More fitting would be German "das geht mir am Arsch vorbei" "it passes me by the ass".

I'd say french je m'en bat les couilles is technically "I slap my balls with it"

How about the Brazilian “I am shitting and walking” (cagando e andando), similar to a horse or donkey that shits while walking and pulling a cart, like it is nothing, without a care in the world…

When I talk about preserving Linguistic Diversity, this is what I mean.

I mean a kilogram of shit is a big shit. Googling says an average shit is half a kilogram (one pound). This is interesting shit.

Less vulgar finnish version

"Kiviäkin kiinnostaa."

i.e. rocks are also interested (about that subject)

I’m Dutch. Never heard of that phrase. They probably mean “It can rust on my ass” “‘t kan me aan mijn reet roesten” still never heard people using that. Is probably regional.

3. I slap my balls on it (French)

If that one sounds weird, the translation misses the point that it's a masturbation reference. It should be "i beat my balls to it". Compare with "je m'en branle", litterally "i jack to it"

That "Spanish" saying is a Spain saying. Things get more colorful in the new world.

Also in French: "it touches one (ball) without moving the other"

"My dick hurts" - various west Balkan languages.

This is why I'm still on the Internet.

I slap my balls with it will be my catchphrase for 2025

I offer "me vale madre" or "me vale verga" n Mexican Spanish.

The first one is weird, madre in this context both does and doesn't mean "mother". It's closer to to the mother in "motherfucker" than it is to "I fucked your mom".

They both mean "I don't give a shit" although with different flavors of vulgarity.

The second one is literally "this means dick to me"

Danish: "Det rager mig en papand"

Lit. "That fondles me (like) a cardboard duck."

Greek Yeah I know of that phrase but it's not really used. It's as funny in Greek as it is in English.

Most common is "on my balls", the short version of I am writing it/him/her on my balls. Implying that you care so little you have the name of it/him/her written on your balls. Yeah it does t make much sense.

The lighter version (you would see in subtitles for example) is "to me there is no nail being burned". I don't know where it comes from. Must be something to do with nails being left behind when you burn wooden structure.

Edit: oh I remembered another; "I shat myself".

Dutch and Greek go unnecessarily hard. Yeah, "I slap my balls on it" is good, but it really does just have the same vibe as "I don't give a fuck." The Greek make it poetic and the Dutch add that specific scientific component that give it that pop.

It concerns me (like) a cardboard-duck. (Danish)

I really like the Dutch one.

In Germany we also have "das geht mir am Arsch vorbei", which translates to "that goes across my ass". It's the more vulgar version of "ist mir wurst" or "it's sausage to me"

Polish would probably be "Mieć wyjebane", which comes from "Mieć wyjebane jajca". It is also balls-related but more like "I have my balls out for that".

In portuguese it would be "tou me pouco cagando" which mean "I'm pooping a little" and I think that it is beautiful.

J’m’en crisse.

"det skiter jag högaktningsfullt i" - with care and respect, i am shitting into it.

"det ger jag inte ett korvöre/ruttet lingon för" - i would not give a sausage cent/rotten lingonberry for it.

"det ger jag själva fan i" - i give satan himself.

Like water on a goose - Swedish

Just thought of one that takes a bit of explanation. In Swedish, much like German, words are joined to create longer words. Such as smörgåsbord(sandwich table). The smurfs in Swedish are therefore called gammelsmurfen (old smurf), "anything"smurfen. Because of this, people jokingly say "intressesmurfen antecknar" ( interest smurf is taking notes) to indicate that they don't care about what somebody is saying

"No me importa un pepino", I don't care about a single cucumber

"Me importa un pepino", shortened version, I care one cucumber, which is what OP was going by probably

Not my circus, not my monkeys. (English)

A few others from french :

J'en parlerai à mon cheval (I'll make sure to tell my horse)
Parle à mon cul, ma tête est malade (Talk to my ass, my head is sick/ill)
Je m'en tamponne le coquillard (no idea how to translate this, but here is a fun explainer, also in french)