Don, still in bed, turned over (3,2)
I believe the answer is:
put on
'don' is the definition.
(I know that don can be written as put on)
'still in bed turned over' is the wordplay.
'still in bed' becomes 'not up' (I've seen this in another clue).
'turned over' shows that the letters should be reversed in order.
'notup' in reverse letter order is 'PUT-ON'.
(Other definitions for put on that I've seen before include "Increase as with weight" , "Affixed" , "Don; mount (a play)" , "in an unnatural way" , "Apply (to a surface) - present (on stage)" .)