Have some of the drink I'd brought back first (3,2)
I believe the answer is:
dig in
'have some of the' is the definition.
I can't tell whether this defines the answer.
'drink i'd brought back first' is the wordplay.
'drink' becomes 'gin' (gin is an alcoholic drink).
'brought back' says the letters should be written backwards.
'first' means one lot of letters go next to another.
'id' backwards is 'di'.
'gin' put after 'di' is 'DIG IN'.
Can you help me to learn more?
(Other definitions for dig in that I've seen before include "Start to eat" , "Begin eating heartily" , "Enjoy the food" , "Start to scoff" , "protect himself" .)