If you want to say that you don’t care about something (as in: “I don’t give a fuck”), in Serbian you would say: “My dick hurts”. And that’s an expression you’ll hear almost daily. A less used variant of that, but still legit is: “My balls are beeping”.

While not insulting, I’ll throw in our way to say: “I’m/You’re fucked”. It’s: “Jebao sam/si ježa u leđa”, which means: “I/You fucked a hedgehog in the back”