Green’s Dictionary of Slang

1. the penis [it wedges open the vagina]; thus v. of a man to have sexual intercourse (see cite c.1850).

a.1720		‘Young Collin’ in Farmer Merry Songs and Ballads (1897) IV 260: Young Collin [...] told his Wife who the Cause would know, / That Hem made the Wedge much further go.
1748–49		Cleland Memoirs of a Woman of Pleasure (1985) 154: He [...] nailed this tender creature with his home-driven wedge.
1790		‘Bumper Allnight. Esquire’ Honest Fellow 106: ‘I drive the wedge further, and make the slit wider’.
1834		‘The Lady’s Water-Spout’ in Randy Songster in Spedding & Watt (eds) I 209: But, says he, I can see, that before I begin, / To stop up the hole I a wedge must thrust in / [...] / Then down on his knees hard at it went he, / He thrust in his wedge as tight as could be, / Drive away, said the lady, go it pell mell.
c.1850		Peeping Tom (London) 20 78/2: ‘I plainly see [...] your front (c—) is in danger of falling [...] The only remedy is you cause the same to be rewedged as hard and as often as you can’.
c.1864		‘The Water-Spout’ in Rakish Rhymer (1917) 72: He drove his wedge into the top, / But soon found it did fit ill.
c.1886		Tilly Touchitt 38: He sought with steady force to send the stiff in-driven wedge home to its ultimate destination.
1890–1904		Farmer & Henley Sl. and Its Analogues.
1941		in G. Legman Limerick (1953) 248: A horny young fellow named Redge / Was jerking off under a hedge. / The gardener drew near / With a huge pruning shear, / And trimmed off the edge of his wedge.

2. (US campus) in fig. use, a derog. term for a hard worker.

1967–8

Baker et al. CUSS 219: Wedge A person who studies a great deal.