Fool in bed on hard coarse material (9)
I believe the answer is:
sackcloth
'coarse material' is the definition.
(I've seen this before)
'fool in bed on hard' is the wordplay.
'fool in' becomes 'clot' (I can't explain this - if you can you should believe this answer much more).
'bed' becomes 'sack' (e.g. 'in the sack').
'on' is a charade indicator (letters next to each other).
'hard' becomes 'h' (abbreviation used in pencil classifications).
'clot' put after 'sack' is 'sackclot'.
'sackclot'+'h'='SACKCLOTH'
Can you help me to learn more?
(Other definitions for sackcloth that I've seen before include "Penitent's attire" , "In which penitent is" , "Sign of penitence" , "Coarse cloth, with ashes it symbolises penitence" , "Penitent's garb" .)