Quickly deflate favourite doll (6)
I believe the answer is:
poppet
'doll' is the definition.
(I know that doll can be written as poppet)
'quickly deflate favourite' is the wordplay.
I cannot quite see how this works, but
'favourite' could be 'pet' (synonyms) and 'pet' is located in the answer.
The remaining letters 'pop' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for poppet that I've seen before include "dear" , "Sweet little darling" , "Term of endearment" , "Term of affection for a child or sweetheart" , "adorable child" .)