Lucky animal in mum's bed (6)
I believe the answer is:
mascot
'lucky animal' is the definition.
I know that 'lucky' relates to this answer. I also know that both the answer and definition are singular nouns
'mum's bed' is the wordplay.
'mum's' becomes 'ma's' (ma can mean mother).
'bed' becomes 'cot' (cot is a type of bed).
'mas'+'cot'='MASCOT'
'in' is the link.
Can you help me to learn more?
(Other definitions for mascot that I've seen before include "Team's good-luck bringer" , "Good-luck charm" , "One is lucky" , "Thing considered to bring good luck" , "Lucky thing" .)