Slightly move the jug (4)

I believe the answer is:

stir

I believe this clue is a double definition.

'slightly move' is the first definition.
(I know that to stir is to move slightly)

'the jug' is the second definition.
(both are slang for prison)

(Other definitions for stir that I've seen before include "Move around in a liquid" , "Mix round" , "A slangy prison - whisk it" , "Bustle, activity" , "Whisk, agitate" .)

I've seen this clue in The Times.

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