Get mother to request material (6)
I believe the answer is:
damask
'material' is the definition.
(damask is a kind of material)
'get mother to request' is the wordplay.
'get' means one lot of letters go next to another.
'mother' becomes 'dam' (female parent of an animal).
'to request' becomes 'ask' (to ask is to request something).
'dam' next to 'ask' is 'DAMASK'.
(Other definitions for damask that I've seen before include "Figured material" , "Table linen material" , "Fine linen with woven pattern" , "Patterned material" , "Heavy patterned fabric" .)