Return to check little girl's tucked in (6)
I believe the answer is:
rejoin
'return to' is the definition.
'check little girl's tucked in' is the wordplay.
'check' becomes 'rein' (both can mean to control or limit).
'little girl' becomes 'jo' (short for Josephine).
'tucked in' means one lot of letters goes inside another.
'rein' placed around 'jo' is 'REJOIN'.
(Other definitions for rejoin that I've seen before include "Return" , "renew subscription" , "Unite again" , "counter" , "Become a member again" .)