Instantly enjoy, when spicy (4,1,4)
I believe the answer is:
like a shot
'instantly' is the definition.
(I've seen this before)
'enjoy when spicy' is the wordplay.
'enjoy' becomes 'like' (I've seen this in another clue).
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'spicy' becomes 'hot' (synonyms).
'like'+'as'+'hot'='LIKE A SHOT'
(Other definitions for like a shot that I've seen before include "Instantly" , "Lout" , "Bally" , "What serious drinkers do" , "right now?" .)