Dating drunk drinking fashionable cocktail (3,3,2)
I believe the answer is:
gin and it
'cocktail' is the definition.
(gin and it is a kind of cocktail)
'dating drunk drinking fashionable' is the wordplay.
'drunk' is an anagram indicator.
'drinking' means one lot of letters goes inside another.
'fashionable' becomes 'in' ('in' can be similar in meaning to 'fashionable').
'dating' is an anagram of 'gandit'.
'gandit' placed around 'in' is 'GIN AND IT'.
(Other definitions for gin and it that I've seen before include "Alcoholic mixed drink" , "A tipple" , "Kind of cocktail consumed in dating" , "Commmitting double marriage" .)