Mate joining ace band pleased as Punch (4-1-4)
I believe the answer is:
cock-a-hoop
'pleased as punch' is the definition.
I can't tell whether this defines the answer.
'mate joining ace band' is the wordplay.
'mate' becomes 'cock' (both are terms of affection).
'joining' says to put letters next to each other.
'ace' becomes 'a'.
'band' becomes 'hoop' (hoop is a kind of band).
'cock'+'a'+'hoop'='COCK-A-HOOP'
Can you help me to learn more?
(Other definitions for cock-a-hoop that I've seen before include "Overjoyed" , "In high spirits" , "Exultant" , "Pleased and triumphant, like rooster with hula toy" , "Ecstatic" .)