stir your stumps
stir (one's) stumps
1. To start moving. "Stumps" are a slang term for "legs." You kids have been sitting around playing video games all day—it's time to get outside and stir your stumps!
2. To increase one's pace while doing some activity. Stir your stumps! We've got to move faster if we want to finish our run before sundown.
stir your stumps(of a person) begin to move or act. British informal , dated
Stump has been used as an informal term for ‘leg’ since the 15th century; the expression itself dates from the mid 16th century.
stir your ˈstumps(old-fashioned, British English, informal) begin to move; hurry: You stir your stumps and get ready for school, my girl!
Stump is an informal word for ‘leg’.