Fooling around leaves head dribbling (9)
I believe the answer is:
trickling
'dribbling' is the definition.
('trickle' can be a synonym of 'dribble')
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for trickling that I've seen before include "dribbling" , "going slowly" , "Flowing slowly" , "Flowing in a small stream" , "moving in little stream" .)