Drink up and hang around for a piece of cake (8)
I believe the answer is:
pushover
'for a piece of cake' is the definition.
('pushover' can be a synonym of 'piece of cake')
'drink up and hang around' is the wordplay.
'drink up' becomes 'pus' (I've seen this in other clues).
'and' is a charade indicator (letters next to each other).
'hang around' becomes 'hover' (hover can mean to linger or hang around).
'pus'+'hover'='PUSHOVER'
(Other definitions for pushover that I've seen before include "upset" , "Person easily convinced or deceived - or shoved down" , "No challenge" , "Topple - easy opponent" , "Child's play, piece of cake" .)