Mother queuing up to take drugs (8)
I believe the answer is:
mainline
'take drugs' is the definition.
The definition and answer can be both related to consumption as well as being verbs in their base form.
Perhaps you can see a link between them that I don't see?
'mother queuing up' is the wordplay.
'mother' becomes 'ma' (Ma is another word for mother or mum).
'queuing up' becomes 'inline' (I can't justify this - if you can you should give a lot more credence to this answer).
'ma'+'inline'='MAINLINE'
'to' is the link.
(Other definitions for mainline that I've seen before include "Inject drug - principal rail connection" , "use drug" .)