Help to smuggle cocaine: tips for drug users (4,5)

I believe the answer is:

acid heads

'drug users' is the definition.
(acid head is a kind of drug user)

'help to smuggle cocaine tips for' is the wordplay.
'help' becomes 'aid' ('aid' can be a synonym of 'help').
'to smuggle' means one lot of letters goes inside another (smuggle can mean to secretly carry).
'cocaine' becomes 'c' ('C' can be a synonym of 'cocaine').
'tips for' becomes 'heads' (I can't justify this - if you can you should give a lot more credence to this answer).
'aid' enclosing 'c' is 'acid'.
'acid'+'heads'='ACID HEADS'

I've seen this clue in The Guardian.

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