Crossword Genius

A punch in the mouth for Sonic's friend with timeless sorceress (7,8)

Ross

I believe the answer is:

knuckle sandwich

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

'a punch in the mouth' is the definition.
(I've seen this in another clue)

'sonic's friend with timeless sorceress' is the wordplay.
I cannot quite understand how this works, but
'with' could be 'and' and 'and' is located in the answer.
This explanation may well be incorrect...

'for' is the link.

Can you help me to learn more?

(Other definitions for knuckle sandwich that I've seen before include "Buffet" , "Slug" , "Punch in mug" , "hit" , "piece of pork between slices of bread" .)

I've seen this clue in The Daily Express.
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