Dance in two prisons (6)
I believe the answer is:
cancan
'dance' is the definition.
(cancan is a kind of dance)
'two prisons' is the wordplay.
'two prisons' can mean two replacements for 'prison'.
'prison' becomes 'can' (the can is American slang for prison).
'prison' becomes 'can' (the can is American slang for prison).
'can'+'can'='CANCAN'
'in' acts as a link.
(Other definitions for cancan that I've seen before include "High-kicking French dance, once considered naughty" , "Dance of the French music halls" , "Kicking entertainment" , "Parisian stage dance" , "from 23a [LA VIE PARISIENNE]?" .)