Cheek raised on soft cushion (6)
I believe the answer is:
pillow
'cushion' is the definition.
(pillow is a kind of cushion)
'cheek raised on soft' is the wordplay.
'cheek' becomes 'lip' (both can mean insolence or rudeness).
'raised' says the letters should be written in reverse.
'on' means one lot of letters go next to another.
'soft' becomes 'low' ('low' can be similar in meaning to 'soft'**).
'lip' reversed gives 'pil'.
'pil'+'low'='PILLOW'
(Other definitions for pillow that I've seen before include "Sleeper's cushion" , "Item of bedding" , "place to lay his head" , "Rest for the weary head" , "Soft place for the head" .)