Green’s Dictionary of Slang

milk v.

1. in senses of taking illegally.

(a) to defraud, to extract money from.

[UK]Frith Disputacion Purgatorye n.p.: To Rdr. Avj, This theyr painful purgatorye [...] hath of longe time but deceaued the people and mylked them from theyr monye [OED].
[UK]C. Walker Authentick Memoirs of Sally Salisbury 109: He had been forc’d to promise to bring her some Rich Cull, whom she might Milk to good Advantage.
[UK]Scoundrel’s Dict. 25: There if Lour we want I’ll milk / a gage or nip from thee a bung.
[UK]G. Hangar Life, Adventures and Opinions II 60: Your flash-man, is following his occupation, scampering on his prancer upon the high tober or at some country fair mulking [sic.] the flatts of the quid.
[US]R.F. Burton City of the Saints 255: ‘Milking the Gentiles,’ coining ‘Bogus-Money, whistling and whittling’.
[UK]Sporting Gaz. (London) 18 Dec. 4/2: The Duke of Beaufort [...] have heard the term milking. Mr Serjeant ballantine: Does it imply swindling?—Witness: Certainly [...] Milking [is] laying against your own horse, and then scratching him, and that is what I consider to be swindling.
[US]W.W. Fowler Ten Years In Wall Street 32: The ring, to use a Wall Street phrase in this way, ‘milk the street,’ taking money out of the bears, who sell at a low price; and out of the bulls, who buy at a high price.
[UK]Sl. Dict. 225: Milking, is keeping a horse a favourite, at short odds, for a race in which he has no chance whatever, or in which he will not be allowed to try, for the purpose of laying against him.
[UK]F. Gilbert ‘I’m the Fellow that Tells the Truth’ 🎵 Our statesmen all ‘milk’ us, our purse is the ‘Cow’ .
[Aus]Truth (Sydney) 14 Apr. 3/6: Some men join the Shearer’s Union for the purpose of ‘milking’ the men of their hard-earned cheques after the shearing is over.
[Aus]Sun. Times (Perth) 8 Mar. 1/1: The now handsome-dividend-paying concern has been vigorously milked by the manager.
[US]M.C. Sharpe Chicago May: Her Story in Hamilton (1952) 131: Sometimes [the blackmailer] exposes the dupe after he has been milked dry.
[US]R. Chandler ‘Goldfish’ Red Wind (1946) 169: Peeler played with a girl and she milked him.
[US]Mezzrow & Wolfe Really the Blues 84: Beefy cattlemen who were sure to be milked.
[US]Lait & Mortimer USA Confidential 19: They milk treasuries of companies in which they infiltrate.
[US]S. Greenlee Spook who Sat by the Door (1972) 31: This was the easiest trick she had in a week. She wondered how much she could milk him for.
[US]L. Kramer Faggots 81: Häagen Dazs up to a buck a cone at the pot-bellied gouger’s. Milk the faggots dry.
[UK]A-Team Storybook 33: We’re all here to milk the suckers.
[Aus]G. Disher Deathdeal [ebook] ‘[A] ring of scam artists is in town. They milked a couple of million off some places in Reno’.
[US]C. Hiaasen Lucky You 175: I’ve got to milk ’em for all they’re worth.
[UK]Guardian Editor 7 Jan. 13: What’s done for the wise guys is the decline of the blue-collar unions, whose pension funds they used to milk.

(b) to intercept telegrams addressed to others.

[UK]Times 14 Aug. in Brewer Phrase and Fable (1894) II 1212/1: ‘Telegram.’ They receive their telegrams in cipher to avoid the risk of their being milked by rival journals .
Milk Journal n.p.: Milking the wires is telegraphic slang for tapping the wires [F&H].
[UK]Sat. Rev. (London) 10 May 607: The Central News telegram, if it was milked at all, was milked throught the medium of Sir C.Wilson’s, etc [F&H].

(c) to be susceptible to fraud, financial manipulation.

[UK]Mirror of Life 11 Apr. 3/4: Fitz won’t ‘milk’ any better than a dry cow.

(d) (Aus.) to siphon petrol from a car (whether legally or not).

[Aus]K. Tennant Foveaux 212: [He] supported both a motor-car and bicycle due to his economical use of the company’s petrol. In one of the shops on his run he kept a big oil drum and when occasion offered he would refill this without expense by the simple expedient of crawling under his ’bus and ‘milking’ her.
[Aus]J. Davis Dreamers 78: roy: Hope they don’t come round lookin’ for boondah for petrol to git ’ome. [...] peter: Don’t you know how to milk a bowser?

2. to masturbate oneself or someone else; to cause to ejaculate [note in D’Urfey, Pills to Purge Melancholy (1719): ‘But stupid Honesty; / May teach her how to Sleep all Night / And take a great deal more Delight, / To Milk the Cows than thee’; note milk n.].

[UK]Jonson Alchemist III iii: For she must milk his epididimis. / Where is the doxy?
[UK]N. Ward London Terraefilius II 20: That Airy Lass [was] brought from the Innocent Squeezing of Cows Dugs, to the Wicked Milking of Town Bulls.
[UK]Harris’s List of Covent-Garden Ladies 53: [He] married her and put her in lodgings, where besides milking him, she sometimes employs her leisure hours in handling other teats, and is said to only a delicate hand at stroking, but great skill in the use of the churn, soon making love’s butter from nature’s cream.
[UK]‘The Blue Vein’ in Hilaria 61: For the squire and curate, when heated with ale, / Doll Dairy had milk’d in her amorous pail.
[UK] ‘Milking The Bull’ in Lummy Chaunter 92: In short, I never was before / Pleas’d half so much, I vow, / So ever since I milk young Hodge, / Before I milk my cow.
[US]Wkly Rake (NY) 9 July n.p.: Another [lover] wanted to be a cow, that his dear might milk him.
[Aus]Satirist & Sporting Chron. (Sydney) 25 Mar. 1/2: The Lady in Elizabeth Street [...] is already sufficiently notorious in the milking of Goats and Stallions.
[UK]‘Three Chums’ in Boudoir IV 130: All three spent quite another hour in f—g, groping, and kissing, till at last Charlie was milked as dry as a stick.
[UK]‘Mary Suckit’ Yvonne 42: Deliver my bursting cockey; suck it, milk it!
P. Kanto Lay-a-day 74: I was milking his cock, making the seminal fluid come out of it.
R. Alley Last Tango in Paris (1980) 133: Paul climaxed, and Jeanne withdrew her hand in disgust. She had milked him, and the last of his strength drained away.
[US]Murray & Murrell Lang. Sadomasochism 95: milking n. Repeated masturbation of a male masochist.
Milkers.com 🌐 Just Awesome, Jaw-Dropping, Dick-Milking JO Fun!

3. (Aus.) to drug or otherwise ensure that a horse will lose a race.

[Aus]Brisbane Courier 10 July 3/5: Such terms as ‘milking,’ ‘roping,’ ‘dead ’uns,’ &c., are highly suggestive, and it is quite probable each may be applicable to one or more horses amongst the sixty-five nominated for the Cup.
Eve. Jrnl (Adelaide, SA) 1 Oct. 3/3: [T]he only safe horse in any race is a ‘dead’ un’ or one that has been ‘milked,’ or ‘made safe’.

4. to add milk to tea or coffee.

Princeton University WordNet 1.7.1 🌐 The verb ‘milk’ has 3 senses in WordNet. 1. milk -- (take milk from female mammals; ‘Cows need to be milked every morning’). 2. milk -- (exploit as much as possible; ‘I am milking this for all it’s worth’). 3. milk -- (add milk to; ‘milk the tea’).

5. to laze around, to be idle.

[UK]A. Morrison Tales of Mean Streets (1983) 38: Milkin’ about at ’ome an’ ’idin’ money.
[US]Eble Campus Sl. Apr. 7: milk around – act in a carefree and lazy manner: ‘I should have been getting some work done, but I’ve just been milking around all afternoon’.

In phrases

milk a duck (v.)

(US) to attempt the impossible.

J.M. Pickard K’ang Ch. 12 on digitalZendo 🌐 Gutha! It would be easier to milk a duck!
milk the goat (v.)

(Aus.) for a bookmaker to defraud a bettor.

[Aus]Sydney Sportsman (Surry Hills, NSW) 11 May 1/2: I present him with a bit of good advice, and it is: whenever he ‘milks the goat,’ never to strip her quite ‘dry’.