Extremely lazy? Lie on bed for a change (4,4)
I believe the answer is:
bone idle
'extremely lazy?' is the definition.
(bone idle means very lazy)
'lie on bed for a change' is the wordplay.
'for a change' indicates anagramming the letters.
'lie'+'on'+'bed'='lieonbed'
'lieonbed' anagrammed gives 'BONE-IDLE'.
(Other definitions for bone idle that I've seen before include "Utterly lazy, won't do a tap" , "Extremely lazy" , "Very lazy, may be ossified?" , "Constitutionally lazy" , "Really lazy in ossified way" .)