plum tree, n. — Green’s Dictionary of Slang

plum tree n.

1. the vagina; thus plum tree shaker, the penis .

c.1547		Marriage of Witt and Wisdome 16: I was neuer stained but once falling out of my mother’s plumtre.
1592		Shakespeare Henry VI Pt 2 II i: car.: What, art thou lame? [...] suf.: How cam’st thou so? simp.: A fall off of a tree. wife: A plum tree, master.
1596		Nashe Have With You to Saffron-Walden in Works III (1883–4) 168: Yea, Madam Gabriela, are you such an old ierker? then, Hey ding a ding, vp with your petticoate, haue at your plum-tree.
1611		R. Cotgrave Dict. of Fr. and Eng. Tongues n.p.: hoche-prunier, a Plum-tree shaker; a man’s yard.
1611		Middleton No Wit or Help like a Womans (1657) II i: If conceit will strike this stroke, have at the Widows Plum-tree.
1627		W. Hawkins Apollo Shroving IV i: If I had bin an Ape I should haue climed plum-trees brauely.
1890–1904		Farmer & Henley Sl. and Its Analogues.

2. the penis [? plum n.¹ (1)].

1611

Tourneur Atheist’s Tragedy IV i: What’s here? a Medlar with a Plum-tree growing hard by it; ... The Plum-tree (forsooth) growes so neare the Medlar, that the Medlar suckes and drawes all the sap from it.

3. (US) the spoils of political office; thus shake the plum-tree v., to extract graft from one’s office [one shakes the fig. ‘tree’ to gain the plum n.² (4)].

1904		Newark Eve. News 27 June 6: It is pretty tough to shut the statesmen off from one of the biggest branches of the plum tree in this summary fashion [DA].
1926		Wood & Goddard Dict. Amer. Sl. 40: plum-tree, shake the. Distribute political patronage.
1952		G. Stimpson Bk about Amer. Politics 258 While he [i.e. Matthew Stanley Quay] was State treasurer (1885–1887) he placed large sums of State money in the People’s Bank of Philadelphia and used it to buy stocks on margin. On one occasion Quay and his associates piled up orders for the stock of the Metropolitan Railroad of New York until only about $10,000 was left in the bank. John S. Hopkins, the cashier, became frightened and protested to the political boss. Quay sent the cashier the message: ‘Buy and carry a thousand Met for me and I will shake the plum tree.’.