Causes excitement in prison with drink (5,2)
I believe the answer is:
stirs up
'causes excitement' is the definition.
'prison with drink' is the wordplay.
'prison' becomes 'stir' (informal term for prison).
'with' is a charade indicator (letters next to each other).
'drink' becomes 'sup' (I've seen this before).
'stir'+'sup'='STIRS UP'
'in' acts as a link.
(Other definitions for stirs up that I've seen before include "causes agitation" , "Agitates" .)