my ass!
US /maɪ æs/
UK /maɪ æs/

1.
meu rabo, nem a pau, que nada
an exclamation used to express strong disagreement, disbelief, or contempt
:
•
He said he'd help, my ass!
Ele disse que ia ajudar, meu rabo!
•
You think you're smart? My ass!
Você se acha inteligente? Meu rabo!