Green’s Dictionary of Slang

prong n.

also pronger

1. the penis, esp. when erect.

[UK] ‘Sally Duff’ in Frisky Vocalist 22: All day she did long / For a taste of the boys’ little magical prong.
[UK]Confessions of Lady Beatrice 4: I felt the pronging of his prong. His hand cupped my nest.
[US]‘Ballad of Gaffer Hepelthwaite’ in Immortalia 2: That never yet a maiden did confront his aged e’en / Whose legs he did not yearn to part and place his prong between.
[US] ‘Hairbreadth Harry in “The Rescue”’ [comic strip] in B. Adelman Tijuana Bibles (1997) 18: With one stroke I shall send my prong into your belly.
‘Cats on the Rooftops’ in Mess Songs & Rhymes of RAAF 1939-45 1: You should hear his high crescendo when his mate is on the prong.
[US](con. 1927) in Randolph & Legman Ozark Folksongs and Folklore (1992) II 618: P is for prick, the petrified prong.
[US]B. Jackson Get Your Ass in the Water (1974) 213: P is for prick, a pastified [petrified] prong, / they ranks from seven to twelve inches long.
[UK]G.F. Newman You Flash Bastard 127: One hand clasped his scrotum while the other stroked the underside of his penis appraisingly. ‘This prong will look quite fetching on me.’.
[US]L. Bangs in Psychotic Reactions (1988) 235: I doubt if there are very many gigs where he doesn’t end up pogoing his pronger in some sweet honey’s hive.
[US]Maledicta IV:2 (Winter) 194: A pointed weapon may be involved, such as a pike, prong, pronger, harpoon.
[UK]T. Paulin ‘As a White Lodge in a Garden of Cucumbers’ in Liberty Tree 17: Hilarious, his prong; / what a scream her fanny is.
[US]G. Indiana Rent Boy 8: He shifted [...] around to show off his partly stiff prong.
[NZ]A. Duff Jake’s Long Shadow 70: You need to get yourself [...] a nice white boy. Yo. With a big pronger you can hold onto while you’re givin’ it to ’im up the rear.

2. a finger.

[UK]Morn. Chron. (London) 12 Apr. 6/3: [Crockford] generally had some thousands of Bank of England notes pinned to the table before hin by the dainty, flexible fingers [...] the fifties, twenties, and tens, under his three longer ‘prongs,’ and a sheet of ‘fivers’ under the guardiansshiip of his little finger.

3. (drugs) a hypodermic syringe.

[US]A.J. Pollock Und. Speaks n.p.: Prong, a hypodermic needle.

In compounds

prong-on (n.)

an erection.

[US]G.V. Higgins Cogan’s Trade (1975) 162: I got this huge prong on and I gotta practically stand on my head if I wanna piss in the hopper.

In phrases

get the prong (v.)

(US) to suffer.

H. Green ‘Troubles of two Working Girls’ in S.F. Chron. 8 June 31/2: I hate to see a good fella get the prong, biut they’ll be hoistin’ him aboard the flewy for Matteawan yet, dearier.