Go for a shower ... (6)
I believe the answer is:
pepper
'shower' is the definition.
(I've seen this before)
'go for a' is the wordplay.
'go' becomes 'pep' (I've seen this before**).
'for' is a charade indicator (letters next to each other).
'a' becomes 'per'.
'pep'+'per'='PEPPER'
(Other definitions for pepper that I've seen before include "Sprinkle liberally" , "Pelt" , "Pungent spice" , "hit by gunshot" , "Spicy condiment" .)