Buzzer initially put in behind drawer in pub (4,4)
I believe the answer is:
beer pump
'drawer in pub' is the definition.
(a beer pump draws up beer)
'buzzer initially put in behind' is the wordplay.
'buzzer' becomes 'bee' (insect which buzzes).
'initially' says to take the initial letters.
'in' indicates putting letters inside.
'behind' becomes 'rump' (informal term for the buttocks).
The initial letter of 'put' is 'p'.
'p' inserted within 'rump' is 'rpump'.
'bee'+'rpump'='BEER-PUMP'
(Other definitions for beer pump that I've seen before include "held in pub" , "one used to draw in locals" .)