Sunshade under pressure popping (7)

I believe the answer is:

pawning

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'popping' is the definition.
Although both the answer and definition are present participle verbs, I can't understand how they can define each other.

'sunshade under pressure' is the wordplay.
'sunshade' becomes 'awning' (synonyms).
'under' says to put letters next to each other.
'pressure' becomes 'p' (abbreviation).
'awning' after 'p' is 'PAWNING'.

Can you help me to learn more?

I've seen this clue in The Times.

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