Drink part of a bottle (4)
I believe the answer is:
neck
I believe this is a double definition.
'drink' is the first definition.
(to neck a drink is to drink it quickly)
'part of a bottle' is the second definition.
(I've seen this in another clue)
(Other definitions for neck that I've seen before include "that's inserted in collar" , "Body part associated with impudence" , "A hard one shows some nerve" , "sink" , "Cervix" .)