Back to the bar for a binge (5)
I believe the answer is:
revel
'a binge' is the definition.
(thesaurus)
'back to the bar' is the wordplay.
'back' says the letters should be written in reverse.
'to the bar' becomes 'lever' (lever is a kind of bar).
'lever' reversed gives 'REVEL'.
'for' acts as a link.
(Other definitions for revel that I've seen before include "Celebrate with a lever, strangely" , "Lever (anag.)" , "Make merry, whoop it up" , "Take part in lively and noisy festivities" , "Paint the town red" .)