Undergarment’s wrong on guys in parade — a bugler must play through it! (5,10)

'a bugler must play through it' is the definition.
I don't know anything about this answer so I cannot judge whether this works.

'undergarment's wrong on guys in parade' is the wordplay.
I cannot quite see how this works, but
'undergarment's' could be 'bras' (bra is a kind of undergarment) and 'bras' is found in the answer.
'wrong' could be 'sin' (wrong can mean a sin or crime) and 'sin' is found in the answer.
'guys' could be 'men' (guy can mean a man) and 'men' is located in the answer.
'parade' could be 'strut' (as in strutting or parading around) and 'strut' is found within the leftover letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?