Squanders benefit on drink (4,2)
I believe the answer is:
uses up
'squanders' is the definition.
'benefit on drink' is the wordplay.
'benefit' becomes 'use' (I've seen this before).
'on' says to put letters next to each other.
'drink' becomes 'sup' (I've seen this before).
'use'+'sup'='USES UP'
(Other definitions for uses up that I've seen before include "drains" , "'Depletes (4,2)'" , "Consumes" , "Exhausts" .)