Spooner's favourite cuddly toy that is used for experiments (4,3)
I believe the answer is:
test bed
'spooner's' is the definition.
Both the answer and definition are singular nouns.
Maybe you can see an association between them that I don't see?
'favourite cuddly toy that is used for experiments' is the wordplay.
I cannot really understand how this works, but
'is' could be 'be' and 'be' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for test bed that I've seen before include "engineers are working on it" , "Practise sleeping" , "place for experimental trials" , "trial equipment" .)