Tease us going back for sweetener (5)
I believe the answer is:
sugar
'sweetener' is the definition.
(sugar is a kind of sweetener)
'tease us going back' is the wordplay.
'tease' becomes 'rag' ('rag' can be a synonym of 'tease').
'going back' says the letters should be written in reverse.
'rag'+'us'='ragus'
'ragus' written backwards gives 'SUGAR'.
'for' is the link.
(Other definitions for sugar that I've seen before include "Mild oath (granulated?)" , "Make more palatable" , "Cane or beet sweet stuff" , "e.g. Glucose" , "White or brown sweetener" .)