Have a tantrum (5,1,6)
I believe the answer is:
throw a wobbly
'have a tantrum' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for throw a wobbly that I've seen before include "Become very angry" , "Suddenly blow a fuse" , "Have a tantrum (colloq.)" , "Go ballistic" , "Have a fit" .)