Something used for wiping bum (6)
I believe the answer is:
sponge
'bum' is the definition.
(take money from someone without reciprocating)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for sponge that I've seen before include "Freeload" , "Wipe" , "'Porous, absorbent substance (6)'" , "Bathroom scrubber" , "mop" .)