Take advantage of jerk to get drink (9)

I believe the answer is:

milkshake

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'drink' is the definition.
(I know that milkshake is a type of drink)

'take advantage of jerk' is the wordplay.
'take advantage of' becomes 'milk' (I've seen this in another clue).
'jerk' becomes 'shake' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'milk'+'shake'='MILKSHAKE'

'to get' acts as a link.

Can you help me to learn more?

(Another definition for milkshake that I've seen is " Cold whisked drink".)

I've seen this clue in The Guardian.

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