Green’s Dictionary of Slang

covered way n.

the vagina.

1750		Love at First Sight 68: [I]t would [...] warm and invigorate their Members to such a Degree of Firmness, as to enable them to stand stffly to the Work they take in Hand [...] to storm the Covered Way, and enter the deepest Intrenchments, and face the hottest Discharge of the Enemy's Fire.
1768		Gentleman’s Bottle-Companion 8: The siege began, unmask’d she lay, / He quickly gain’d the cover’d way.
1787		Harris’s List of Covent-Garden Ladies 75: [She] does not refuse any visitant who able to cover his approaches to her covered work with one pound note.
1788		‘The Gobbio’ Chap Book Songs 7: And soon he got on the cover’d way, / He battered a breach, but missed his reach.
1790		‘Bumper Allnight. Esquire’ Honest Fellow 8: For none but dear Shandy she said, / Shou’d dance upon her cover’d way.
1890–1904		Farmer & Henley Sl. and Its Analogues.
1896		Farmer Vocabula Amatoria (1966) 194: Navire, n. The female pudendum; ‘the covered way’.