Green’s Dictionary of Slang

duck’s arse n.

also duckass, duck bum, duck-fanny, duck’s ass, …butt
[SE duck + arse n. (1)/ass n. (2)/bum n.1 (1)/fanny n.1 (3)/butt n.1 (1a)]

1. (orig. US) a type of hairstyle, esp. as adopted by teddyboys and rockers, in which the back of the hair is turned upwards in a manner similar to a duck’s tail; note unusual adv. use in cit. 1961.

[US]H. Ellison ‘No Game for Children’ in Gentleman Junkie 76: He had brown hair that he wore duck-ass.
[[US](con. 1953–7) L. Yablonsky Violent Gang (1967) 84: Zoot yourself and plaster your hair until it looks like a duck’s behind].
[US]M. Braly Shake Him Till He Rattles (1964) 23: His hair was long and combed into a glossy duck’s-butt.
[US] in S. Harris Hellhole 234: The greatest single affection among the ‘stud broads’ [...] is the close-cropped men’s haircut, ranging from a practical crew to the popular ‘Duck’s Ass.’.
[US](con. 1940s) E. Thompson Tattoo (1977) 45: Bucky was tall [...] with olive skin and long straight black hair he combed meticulously into a perfect duck’s ass.
[US]M. Braly False Starts 44: Everyone tried to avoid the hook to the barber shop, at least long enough to grow the beginning of a duckass.
[Aus]G. Seal Lingo 109: The hairstyle referred to here was usually known as a cornel wilder and was one of a number of US cuts affected by bodgies [...] The rock-and-roll variant of these styles was usually called a duck’s arse.
[UK]Indep. Mag. 9 Dec. 21: The funny haircuts confused people [...] The way they sprang from the forehead like an oily prodding finger, the way that they were called ‘duck’s arse’ and ‘elephant’s trunk’.

2. attrib. use of sense 1.

[US]H. Ellison Web of the City (1983) 143: Black leather jackets, chino slacks, stomping boots [...] duck-fanny haircuts.
[Aus]‘David Forrest’ Hollow Woodheap 179: St. Joseph the Bloody Worker skirted quietly around The Professor, bestowing on the stove-pipe pants and duck bum’s haircut a look of extreme dissatisfaction.
[UK]N. Cohn Awopbop. (1970) 58: He looked like another sub-Elvis, smooth flesh and duck-ass hair.
[US]S. King It (1987) 344: Even when he was the werewolf he still had a sort of a duck’s ass haircut.
[US]R. Price Clockers 33: A forward-thrusting blond-turning-gray duck’s ass haircut.

3. (Irish) a soggy cigarette butt.

[Ire]R. Doyle Paddy Clarke Ha Ha Ha 252: I made sure my lips were dry so I wouldn’t put a duck’s arse on it.
[Ire]G. Coughlan Everyday Eng. and Sl. [Internet] Duck’s Arse (n): wet fag butt.