Some possum tile-hopping backwards? It's in the paper! (6)
I believe the answer is:
litmus
'paper' is the definition.
(litmus paper is a kind of paper)
'some possum tile-hopping backwards?' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'backwards?' is a reversal indicator (I've seen 'backwards' mean this).
'sumtil' is hidden within 'possum tile hopping'.
'sumtil' in reverse letter order is 'LITMUS'.
'it's in the' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for litmus that I've seen before include "Chemical tester" , "Acid-test paper" , "Chemistry lab indicator" , "Substance used in test for acidity" , "A dye used as a rough indicator of acid" .)