Like posh people, pull lush curtains off (3-6)
I believe the answer is:
top-drawer
'like posh people' is the definition.
(top-drawer can mean high social class)
'pull lush curtains off' is the wordplay.
'pull' becomes 'draw' (draw is a kind of pull).
'lush' becomes 'toper' (I've seen this before).
'curtains off' means one lot of letters goes inside another (curtain off can mean to cover up).
'draw' put within 'toper' is 'TOP-DRAWER'.
(Other definitions for top-drawer that I've seen before include "of high social standing" , "Perfect" , "Of the highest standing" , "Excellent" .)