Green’s Dictionary of Slang

two shakes of a lamb’s tail phr.

also fling of a cow’s tail, half a shake of a lamb’s tail, half a shake of a dog’s tail, jerk of a lamb’s tail, three shakes, shake of a lamb’s tail, three shakes of a (dead) lamb’s tail, …of a (dead) sheep’s tail, two flips of a humming-bird’s tail, two shakes of a dead lamb’s tail, …of a (dead) sheep’s tail, …of a duck’s tail, …of a frog’s whisker, …of a gnat’s chuff, …of a lamb’s arse, …of the mainbrace, two jerks of a lamb’s tail, two twists…, two winks of a mole’s eye, whisk of a lamb’s tail

a very short time, usu. with in a..., meaning extremely quickly, at once.

[US]J.H. Ingraham Pierce Fenning 36: ‘Pull sharply.’ ‘Aye, Cap’n, we are there between two winks of a mole’s eye.’.
[US]Hornellsville Wkly Trib. (NY) 3 Dec. 2/3: A natural consequence fetched the whole eternal swarm of yellow-legged varmints about her ears, in less’n half a shake of a lamb’s tail.
[UK]H. Kingsley Hillyars and Burtons (1870) 313: There’ll be high life below stairs with him in about two twists of a lamb’s tail.
[US](con. c.1840) ‘Mark Twain’ Huckleberry Finn 348: Spos’n he can’t fix that leg in just three shakes of a sheep’s tail, as the saying is?
Nebraska State Jrnl (Lincoln, NE) 30 Mar. 6/4: The dog [...] pounced down [...] and in half a shake of a dog’s tail it was captured.
[US]H. Frederic Seth’s Brother’s Wife 384: I’ll shaow him to yeh in th’ jerk of a lamb’s tail.
[US]Arizona Republic (Phoenix, AZ) 29 May 4/3: ‘I can give you the schedule in half a shake of a lamb’s tail’.
[US]Monroe & Northup ‘College Words and Phrases’ in DN II:iii 142: jerk of a lamb’s tail, n. phr. Very short time. ‘I’ll do it in three jerks of a lamb’s tail,’ i.e., very quickly.
[US]G.D. Chase ‘Cape Cod Dialect’ in DN II:vi 429: whisk of a lamb’s tail, n. phr. A very short time.
[US]J.W. Carr ‘Words from Northwest Arkansas’ in DN III:i 98: three shakes of a dead sheep’s tail, n. phr. A trice. ‘I can do that in three shakes of a dead sheep’s tail.’.
[US]C. M’Govern Sarjint Larry an’ Frinds 26: In two shakes of a dead lamb’s tail dey had Larry bound hand and foot.
[US]W.M. Raine Bucky O’Connor (1910) 240: I’m with you in the fling of a cow’s tail.
[US]W.M. Raine Wyoming (1908) 57: I made my getaway about three shakes too soon, by gum!
[UK]A.N. Lyons Arthur’s 273: In less than two shakes of the mainbrace I shall fetch a rope’s-end to you.
[UK]Magnet 20 June 15: You’ll get all the police you want in something less than two shakes of a sheep’s tail.
[US]L.W. Payne Jr ‘Word-List From East Alabama’ in DN III:v 381: three shakes (of a sheep’s tail), n. phr. A very short time, a trice.
[UK]Gem 7 Oct. 13: You’ll have their spears about your ears in a shake of a lamb’s tail.
[US]Van Loan ‘The Spotted Sheep’ in Taking the Count 92: It’s all right, kid. We’ll have you fixed up in three shakes of a lamb’s tail.
[US]P. Kyne Cappy Ricks 248: I decided, in about two flips of a hummingbird’s tail, that it would be a mighty good thing.
[US] in J.F. Dobie Rainbow in Morning 91: I can do it in two shakes of a sheep’s tail. We’ll have it done in three shakes of a dead sheep’s tail.
[US]‘Ellery Queen’ Roman Hat Mystery 117: I’ll be there myself in two shakes of a lamb’s tail.
[UK]Wodehouse Right Ho, Jeeves 169: In two shakes of a duck’s tail Gussie [...] will be distributing the prizes at Market Snodsbury Grammar School.
[US]J. Conroy World to Win 312: I’d better go for help! I’ll be back in three shakes of a dead lamb’s tail.
[US]C. Odets Awake and Sing! Act III: In two shakes of a lamb’s tail, we’ll start a real fight.
[UK]A. Buckeridge Jennings Goes To School 157: The breakfast bell will be going in two shakes of a lamb’s tail.
[UK]Wodehouse Jeeves and the Feudal Spirit 175: In about two shakes of a duck’s tail inspectors and sergeants would come scooping me up.
[UK]G.W. Target Teachers (1962) 173: ‘Won’t be two shakes of a lamb’s what-you-call it,’ he said.
[UK]‘Frank Richards’ Billy Bunter at Butlins 157: We’ll have you back in Camp in two shakes of a frog’s whisker!
[US]T. Williams Night of the Iguana Act II: I won’t be longer than three shakes of a lively sheep’s tail.
[Aus]B. Humphries Barry McKenzie [comic strip] in Complete Barry McKenzie (1988) 23: I’ll be with you in two shakes of a lamb’s arse.
[US]Kerouac letter 27 Aug. in Charters II (1999) 473: We used to get things done in two shakes of a lamb’s tail.
[US](con. 1900s) G. Swarthout Shootist 233: He reached the corner in two jerks of a lamb’s tail.
[US]A. Maupin Tales of the City (1984) 40: I’ll be right back in two shakes of a lamb’s tail.
[NZ]McGill Dict. of Kiwi Sl. 116/1: two shakes of a dog’s hind leg give me a few seconds and I’ll be with you; variant two shakes of a dead lamb’s tail rather less basic.
[UK]Viz Oct.–Nov. 12: We’ll have you down in two shakes of a gnat’s chuff!
[US]Tarantino & Avery Pulp Fiction [film script] 35: I’ll be out within three shakes of a lamb’s tail.
[NZ]McGill Reed Dict. of N.Z. Sl. [as cit. 1988].
[US]S. King Finders Keepers (2016) 160: I’ll be back with it in two shakes of a lamb’s tail.