Green’s Dictionary of Slang

twelve adj.

SE in slang uses

In compounds

twelve godfathers (n.) (also the twelve, twelve apostles) [they ‘give a name’ to one’s crime]

the jury; thus you will be christened by twelve godfathers someday before long.

[UK]J. Dalton Narrative of Street-Robberies 23: They are likely to stop there, till they appear before their twelve God-fathers.
‘On Newgate Steps Jack Chance was Found’ 🎵 He stood the patter but that’s no matter: / He gammoned the twelve and he worked on the water.
[UK]Hotten Sl. Dict.
[Aus]Sydney Sl. Dict. (2 edn) 11: Twelve Godfathers - A jury, because they give a name to the crime a prisoner has committed.
[Aus]Crowe Aus. Sl. Dict. 90: Twelve God Fathers, a jury.
[Aus]Argus (Melbourne) 20 Sept. 6/4: Those who give evidence against him ‘mount the pieter,’ [sic] he is tried by ‘the bloke with the jasey,’ or the high bloke, condemned by the twelve apostles, or the twelve godfathers.
twelve inches (n.) (also one foot, ten inches, thirteen inches, twelve incher)

a (large) penis.

[UK]J. Wilkes ‘Universal Prayer’ in Essay on Woman 24: Save him alike from foolish Pride, / Or impious Discontent; / If greater thickness be denied, / Or thirteen Inches lent.
‘Daniel M’Clean’s Gaucing Instrument’ in Daniel M’Clean’s etc. 2: Where any young Maiden that make application, / To ease her vexation, twelve inches or more, / Of a Triangled weapon of new calculation, / Shall be at her service while ev’r it can bore.
[UK] ‘The Great Unmentionable’ in Fanny Hill’s Bang-up Reciter 20: The thing was twelve inches long, sirs.
[US]B. Jackson Get Your Ass in the Water (1974) 55: Caught the old lady bent over shovelin’ coal, / put twelve inches up her hole.
[UK]F. Pollini Glover 13: Ten inches. That enough? [Ibid.] 56: He’s quite a man [...] Twelve inches.
[US]P. Conroy Great Santini (1977) 312: I might find time to slip her a piece of my Grade A twelve incher.
[NZ]A. Duff One Night Out Stealing 110: It’s only eleven inches — HAHAHA...
[UK]Guardian Rev. 6 Aug. 13: He calls it ‘one feet,’ which even seems to puzzle his backing vocalist. ‘You mean one foot?’ he pleads. ‘Nah, me mean one feet,’ snaps Beanie Man.
twelve penn’orth (n.)

(UK und.) a twelve-month sentence.

in 🌐 ‘[I] was quodded for prigging and had twelve-pennorth at the mill’.