Scandalous dance in two prisons (6)
I believe the answer is:
cancan
'scandalous dance' is the definition.
(the cancan is a raunchy 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 "Lively French stage dance" , "French female chorus line dance" , "Parisian high-kicking dance" , "Leg-kicking dance" , "Chorus-girl dance" .)