Stretches on the bed (6)
I believe the answer is:
sheets
'stretches on the bed' is the definition.
The answer and definition can be both man-made objects as well as being plural nouns.
Maybe there's an association between them I don't understand?
This is all the clue.
Can you help me to learn more?
(Other definitions for sheets that I've seen before include "Pieces of paper and bed linen" , "Bed covers" , "Pieces of paper or bedclothes" , "Bed coverings for the sailor's ropes" , "They get blanket coverage" .)