Good-luck charm mother's put by bed (6)
I believe the answer is:
mascot
'good-luck charm' is the definition.
(I've seen this before)
'mother's put by bed' is the wordplay.
'mother's' becomes 'ma's' (ma can mean mother).
'put by' is a charade indicator (letters next to each other).
'bed' becomes 'cot' (cot is a type of bed).
'mas'+'cot'='MASCOT'
(Other definitions for mascot that I've seen before include "Thing believed to bring good luck to its owner or team" , "Good luck token" , "One is lucky" , "Team's good luck bringer" , "Thing supposed to bring good luck" .)