What fiddler might do? Behave obsequiously (3,3,6)
I believe the answer is:
bow and scrape
'behave obsequiously' is the definition.
(I've seen this before)
'what fiddler might do?' is the wordplay.
I cannot really see how this works, but
'do?' could be 'ape' (both can mean to impersonate) and 'ape' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for bow and scrape that I've seen before include "Be obsequious" , "show subservience" , "Two ways to fiddle" , "Grovel" , "Show humility" .)