A couple of cats have the drum (3-3)
I believe the answer is:
tom-tom
'the drum' is the definition.
(I've seen this before)
'a couple of cats' is the wordplay.
'a couple of cats' can mean two replacements for 'cat'.
'cat' becomes 'tom' (a tom is a male cat).
'cat' becomes 'tom' (a tom is a male cat).
'tom'+'tom'='TOM-TOM'
'have' acts as a link.
(Other definitions for tom-tom that I've seen before include "Cylindrical drum" , "Drum - the piper's son (3-3);" , "Small drum beaten with hands" , "African drum beaten with hands, sounds repetitive" , "Hand-beaten drum" .)