Commanding officer taking short nap after lunch is most comfortable (7)

I believe the answer is:

cosiest

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'is most comfortable' is the definition.
('cosy' can be similar in meaning to 'comfortable')

'commanding officer taking short nap' is the wordplay.
'commanding officer' becomes 'co'.
'taking' is a charade indicator (letters next to each other).
'short' means to remove the last letter.
'nap' becomes 'siesta' (siesta is a kind of nap).
'siesta' with its final letter removed is 'siest'.
'co'+'siest'='COSIEST'

'after lunch' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.

Can you help me to learn more?

(Another definition for cosiest that I've seen is " Most warm and comfortable".)

I've seen this clue in The Guardian.

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