Warble on about the drink (5,3)
I believe the answer is:
brown ale
'drink' is the definition.
(I've seen this before)
'warble on about' is the wordplay.
'about' indicates an anagram.
'warble'+'on'='warbleon'
'warbleon' anagrammed gives 'BROWN ALE'.
'the' acts as a link.
(Other definitions for brown ale that I've seen before include "Type of beer" , "Noble war (anag) - drink" , "Dark, mild beer" , "bottled beer" , "Dark, malty beer" .)