Spread fountain's spray, just not in ... (3,3)

I believe the answer is:

fan out

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

'spread' is the definition.
(fanning out is a kind of spreading)

'fountain's spray just not in' is the wordplay.
I cannot really see how this works, but
'not' could be 'no' (I've seen this in other clues) and 'no' is present in the answer.
This explanation may well be incorrect...

Can you help me to learn more?

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

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