Chatting away, like Jack Sprat’s wife at dinnertime? (7,3,3)

I believe the answer is:
chewing the fat
'dinnertime?' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.
'chatting away like jack sprat's wife at' is the wordplay.
I cannot quite understand how this works, but
'away' could be 'a' (abbreviation as used in sports fixtures) and 'a' is found in the answer.
'wife' could be 'w' (abbreviation) and 'w' is found within the answer.
'at' could be 'in' (synonymous in some cases - eg at school, in school) and 'in' is located in the answer.
'like' could be 'eg' (I've seen this in other clues) and 'eg' is located in the remaining letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for chewing the fat that I've seen is " Gossiping - arguing".)