A kid resting (2,4)
I believe the answer is:
at ease
'resting' is the definition.
(I've seen this in another clue)
'a kid' is the wordplay.
'kid' becomes 'tease' (I've seen this in other clues).
'a'+'tease'='AT EASE'
(Other definitions for at ease that I've seen before include "Free from anxiety,in comfort" , "with no worries" , "unworried" , "'Relaxed (2,4)'" , "Free from anxiety" .)