fish or cut bait
Either proceed with an activity or abandon it completely. For example, You've been putting off calling him for hours; either fish or cut bait. This expression, often uttered as an imperative, alludes to a fisherman who should either be actively trying to catch fish or cutting up bait for others to use. It was first recorded in the Congressional Record (1876), when Congressman Joseph P. Cannon called for a vote on a bill legalizing the silver dollar: "I want you gentlemen on the other side of the House to 'fish or cut bait.'" A vulgar synonym from the 1940s is shit or get off the pot.
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