Die Sau rauslassen

https://www.expath.de/useful-german-idiom-die-sau-rauslassen/

Random German Expression of the Day: “Die Sau rauslassen” – This German expression literally translates as “to let the sow (female pig) out” and, depending on who you are, can be variously translated as “to whoop it up”, “to let one’s hair down”, “to let it all hang out”, “to get loose”, “to bounce until one drops”, “to paint the town red” – in essence, to party without abandon.

“Bei der Party heute lassen sie so richtig die Sau raus.” – “Today they’ll really go crazy at the party.”

Be aware that this expression carries with it a slight connotation of making a public nuisance of oneself… much in the same way a loose pig would.