Some merrymaking in bar, whirling around (5)
I believe the answer is:
revel
'some merrymaking' is the definition.
(revel is a kind of merrymaking)
'bar whirling around' is the wordplay.
'bar' becomes 'lever' (lever is a kind of bar).
'whirling around' is a reversal indicator.
'lever' reversed gives 'REVEL'.
'in' is the link.
(Other definitions for revel that I've seen before include "Feast riotously" , "Spree" , "Be festive, enjoy" , "Have noisy fun" , "Have a few drinks etc." .)