Poke quietly with stick (4)
I believe the answer is:
Here is my best explanation:
'poke' is the definition.
('prod' can be a synonym of 'poke')
'quietly with stick' is the subsidiary indication.
'quietly' becomes 'p' (p for piano and quiet).
'with' says to put letters next to each other.
'stick' becomes 'rod' (I've seen this in other clues).
(Other definitions for prod that I've seen before include "Poke with stiff finger to urge", "Poke; reminder", "Poke or spur", "Poke - remind", "Jab - nudge", "Nudge", "Poke with a stick", "Poke, stimulate into action", "Motivate; jab" and "Push with pointed instrument".)