“Now tell me one about cowboys.”

It is used to express disbelief or skepticism towards a story or excuse that someone is telling.

Translation in spanish

“Ahora cuéntame una de vaqueros.”

Se usa para expresar incredulidad o escepticismo ante una historia o excusa que alguien está contando.

Phonetic:
/Ah-oh-rah kwen-tah-meh oo-nah deh vah-keh-rohs/