Frustrate a sad don desperately wanting liquor (6,3,4)

I believe the answer is:

scotch and soda

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But I can't explain it at all! Could you help me understand?

(Other definitions for scotch and soda that I've seen before include "Simple cocktail" , "Do coach-stands (anag) - alcoholic mixture" .)

I've seen this clue in The Everyman puzzle in The Observer.

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