Roughly shaking awake for drinking session (9)

I believe the answer is:

carousing

'drinking session' is the definition.
(to carouse is to drink alcohol in a boisterous way)

'roughly shaking awake' is the wordplay.
'roughly' becomes 'ca' (abbreviation for circa).
'shaking awake' becomes 'rousing' (rouse can mean to wake up).
'ca'+'rousing'='CAROUSING'

'for' acts as a link.

I've seen this clue in The Guardian.

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