piss in the wind

/P IH1 S IH0 N DH AH0 W AY0 N D/
verb
  1. 1

    To waste time on a pointless or fruitless task; do something that is ineffective or counterproductive.

    โ€œYou can make a complaint if you like, but you'll just be pissing in the wind.โ€

Source: https://en.wiktionary.org/wiki/piss%20in%20the%20wind