Definition of duck's arse in English:

duck's arse

(US duck's ass)

noun

informal
  • A man's hairstyle, associated especially with the 1950s, in which the hair is slicked back on both sides and tapered at the nape.

    • ‘He had dark hair, combed in an elaborate duck's ass, which for some reason didn't look silly on him, and he slouched against the wall with far more grace than his similarly garbed compatriots.’
    • ‘His fine quiff sweeps back dramatically from his forehead down to his comfortable duck's arse.’