PP was right that it means women won't shut up, but specifically it comes from the Scottish independence movement. Those of us who want both independence and to protect women's rights and child safeguarding warned that Indy was being put at risk by the SNP's obsession with trans issues, because we wouldn't vote for our own obliteration. We were told to shut up (haud yer wheesht), work for, vote for, and gain indy, and then women's rights could be addressed. You know, the usual, "after the revolution, meanwhile make the tea" routine.
And years later, SNP support is dropping (although support for Indy remains around the 50% mark), the party has been almost completely captured, and the prospect of Indy has been well and truly kicked down the road. Women still won't wheesht, and I'm proud of us.
(Still want indy, though. 😎 )