Head's rested on this rugby ball perhaps -- that hurt! (6)
I believe the answer is:
pillow
'head's rested on this rugby ball perhaps that hurt' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'ball perhaps that hurt' is the wordplay.
'ball perhaps' becomes 'pill' (humorous term for the ball in some sports. I am not sure about the 'perhaps' bit.).
'that hurt' becomes 'ow' (exclamation of pain).
'pill'+'ow'='PILLOW'
Can you help me to learn more?
(Other definitions for pillow that I've seen before include "Rest for the weary head" , "Item of bedding" , "place to lay his head" , "Bed cushion" , "Sleeper's cushion" .)