He grows in confusion when washing himself (9)

I believe the answer is:

showering

I'm a little stuck... Click here to teach me more about this clue!

'washing himself' is the definition.
I can't tell whether this defines the answer.

'he grows in confusion' is the wordplay.
'confusion' indicates anagramming the letters.
'he'+'grows'+'in'='hegrowsin'
'hegrowsin' with letters rearranged gives 'SHOWERING'.

'when' is the link.

Can you help me to learn more?

(Another definition for showering that I've seen is " naked behind curtain?".)

I've seen this clue in the Sydney Morning Herald.

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