Commanding officers operating silky case (6)
I believe the answer is:
cocoon
'silky case' is the definition.
(I've seen this in another clue)
'commanding officers operating' is the wordplay.
'commanding officers' becomes 'coco' (I can't explain this - if you can you should believe this answer much more).
'operating' becomes 'on' (I've seen this in other clues).
'coco'+'on'='COCOON'
Can you help me to learn more?
(Other definitions for cocoon that I've seen before include "Protective case for insect" , "protective clothing" , "Envelop for protection" , "Protective cover of silkworms, etc" , "Protect" .)