Mate, say, making a fuss (7)
I believe the answer is:
palaver
'a fuss' is the definition.
(I've seen this before)
'mate say' is the wordplay.
'mate' becomes 'pal' (I've seen this before).
'say' becomes 'aver' ('aver' can be a synonym of 'say').
'pal'+'aver'='PALAVER'
'making' is the link.
(Other definitions for palaver that I've seen before include "Song-and-dance" , "Yak" , "Commotion" , "Kind of discussion or idle chatter" , "Long tedious fuss" .)