Approach empty drink bottles (5,2)
I believe the answer is:
sidle up
'approach' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'empty drink bottles' is the wordplay.
'empty' becomes 'idle' (I've seen this in another clue).
'drink' becomes 'sup' (to sup is to drink).
'bottles' means one lot of letters goes inside another (to bottle can mean to contain).
'idle' going into 'sup' is 'SIDLE UP'.
Can you help me to learn more?
(Another definition for sidle up that I've seen is " Come near".)