Maybe use too few items plucked from cushion or bolster (8)
I believe the answer is:
underpin
This clue is a double definition.
'maybe use too few items plucked from cushion' is the first definition.
(use too few pins)
'bolster' is the second definition.
(thesaurus)
'or' acts as a link.
(Other definitions for underpin that I've seen before include "Form the basis for" , "Prop up with nun pride" , "corroborate" , "Support or strengthen from beneath" , "buttress" .)