Lair takes in a member in Gateshead for a spray? (9)

I believe the answer is:

dampening

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'a spray?' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.

'lair takes in a member in gateshead' is the wordplay.
'lair' becomes 'den' (synonyms).
'takes in' is an insertion indicator.
'member' becomes 'MP' (Member of Parliament).
'gateshead' becomes 'g' (head letter of 'gates').
'a'+'mp'='amp'
'den' placed around 'amp' is 'dampen'.
'dampen'+'in'+'g'='DAMPENING'

'for' acts as a link.

Can you help me to learn more?

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

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