Put back beers, period! (4)
I believe the answer is:
stop
'period' is the definition.
(synonyms)
'put back beers' is the wordplay.
'put back' is a reversal indicator.
'beers' becomes 'pots' (large glasses of beer in Australia).
'pots' back-to-front is 'STOP'.
(Other definitions for stop that I've seen before include "Pack it in - bar" , "Don't allow" , "Withhold payment" , "period in US" , "Arrest" .)