Ripple taking marrow from small bone (4,2)
I believe the answer is:
stir up
'ripple' is the definition.
(thesaurus)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for stir up that I've seen before include "Instigate" , "Incite; mix" , "Fire in" , "Foment (trouble)" , "Cause or provoke trouble" .)