Criticise guys going round taking ecstasy (4)
I believe the answer is:
slam
'criticise' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
(Other definitions for slam that I've seen before include "Shut (door) with force" , "A grand one is 13 tricks" , "Hit hard" , "If it's grand, it wins all 13 tricks in bridge game" , "Shut loudly and forcibly" .)