Green’s Dictionary of Slang

arbor vitae n.

the penis.

1732		Ladies Delight 16: The Vulvaria itself being indeed no other than a female Arbor Vitae.
1736		St James’s Register 13: You [i.e. a deserted woman] can’t bear the Loss of your Arbor Vitae.
1784		Rambler’s Mag. June 226/1: The Natural History of the arbor vitae [...] The tree of life is a succulent plant consisting of one only straight stem.
c.1786		Grose Classical Dict. of the Vulgar Tongue ms. additions n.p.: Arbor Vitae. A Man’s Penis.
1798		‘B— ’s Bugbear’ in Hilaria 124: For she yet had a taste for the arbor of life.
1787		Harris’s List of Covent-Garden Ladies 83: She did not want a second invitation [...] to taste the wonderful Tree of Life.
1788, 1796		Grose Classical Dict. of the Vulgar Tongue (2nd, 3rd edn) n.p.: Matrimonial Peace-maker. The sugarstick, or arbor vitae.
1811		Lex. Balatronicum [as cit. 1788].
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue [as cit. 1788].
[1840		‘The Tree of Life’ in Fake Away Songster in Spedding & Watt (eds) Bawdy Songbooks (2011) III 292: ’Tis a faithful description of the Tree of Life, / So pleasing to ev’ry maid, widow and wife!].
1886		R.F. Burton (trans.) Arabian Nights X 239: Of the penis succedaneus, that imitation of the Arbor vitæ, [...] which...the French [call] godemiché [i.e. a dildo].
1890–1904		Farmer & Henley Sl. and Its Analogues.
c.1904		A. Crowley Snowdrops from a Curate’s Garden 32: My own modest arbor-vitae, though, as you may guess, shared no such disabilities.