To go get beer or other alcohol. Used chiefly in the coal region of northeast Pennsylvania. Derived from old coal mining days, when the miners would take a growler (a type of metal bucket) and put their lunch in it, and put their coffee in the bottom in a separate compartment. This was supposedly to keep the meal warm, but it probably didn't work too well. On the way home from work, the miner would "rush the growler" over to the local watering hole and fill it up with cans or bottles of beer to bring home. Hence, rush the growler.
Guy 1: "Yo, butt! I'm gonna go rush the growler, ya want anything?"

Guy 2: "Yeah, get me a couple quarts o' Lager!" ("Lager" always means Yuengling Lager in Northeast PA.)
by SomeGuyFromNEPA January 22, 2009
A practice describing a person going to a saloon with a bucket in order to have it filled up with beer; normally practiced during the 20s-40s. Also known as getting a "scuttle of suds".
Person A: My, he's been in that saloon an awfully long time.
Person B: Ah; that's because he's been rushing the growler.
by IOA94 August 18, 2011