Nudge softly with a stick (4)
I believe the answer is:
prod
'nudge' is the definition.
(I know this)
'softly with a stick' is the wordplay.
'softly' becomes 'p' (short for piano, musical term for softly).
'with' is a charade indicator (letters next to each other).
'a stick' becomes 'rod' (I've seen this before).
'p'+'rod'='PROD'
(Other definitions for prod that I've seen before include "Poke or spur" , "Stimulus" , "Give a reminder" , "Poke with stiff finger to urge" , "Incite to action (with a stick?)" .)