Jerk regularly serves up weak hashish (5)
I believe the answer is:
shake
'jerk' is the definition.
(thesaurus)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for shake that I've seen before include "Shiver" , "Quiver" , "damaging blow" , "Upset" , "Rattle" .)