Queen upset relations getting extensions (7)
I believe the answer is:
annexes
'extensions' is the definition.
('annex' can be a synonym of 'extension')
'queen upset relations getting' is the wordplay.
'queen' becomes 'anne' (Queen Anne, 18th-century queen).
'upset' shows that the letters should be reversed in order.
'relations' becomes 'sex' (euphemism for sex).
'getting' says to put letters next to each other.
'sex' back-to-front is 'xes'.
'anne'+'xes'='ANNEXES'
(Other definitions for annexes that I've seen before include "outbuildings" , "Adds or joins to larger thing" , "Illegally seizes" .)