Stuff the man’s with meat (9)
I believe the answer is:
petersham
'stuff' is the definition.
(I have seen 'Heavy stuff' mean 'petersham' so perhaps 'stuff' could also mean 'petersham')
'man's with meat' is the wordplay.
'man's' becomes 'peters' ().
'with' says to put letters next to each other.
'meat' becomes 'ham' (ham is a kind of meat).
'peters'+'ham'='PETERSHAM'
'the' is the link.
(Other definitions for petersham that I've seen before include "Material" , "Stiffener" , "Ribbed silk ribbon" , "Heavy stuff" , "Corded tape used for stiffening" .)