Green’s Dictionary of Slang

the female genitals.

c.1800		Burns Merry Muses of Caledonia in Works (1842) Some like the lassies that’s gey weel dressed, / And some like the lassies that’s ticht aboot the waist, / But it’s in among the blankets that I like best, / To get a jolly rattle at the cuckoo’s nest.
1833		‘The Cuckoo’s Nest’ in Rummy Cove’s Delight in Spedding & Watt (eds) Bawdy Songbooks (2011) III 116: ’Oh, my dear,’ then she says, ‘I cannot you deny / [...] / You may gently slip a hand on my Cuckoo’s Nest’.
1837–8		‘Tale Of A Shift’ in Cuckold’s Nest 35: Her lover was a perfect pest, / He tore me off (I do not jest), / And travelled into her cuckoo’s nest.
1842		‘When I Beheld a Maidenhead’ in Nancy Dawson’s Cabinet of Songs 31: I longed [...] Slap in the cuckoo’s nest to be.
c.1850		Peeping Tom (London) 12 48/3: [advert] jolly companion — Cuckoo’s Nest.
1870		Cythera’s Hymnal 28: For crabs infest the cuckoo’s nest.
1890–1904		Farmer & Henley Sl. and Its Analogues.
1896		Farmer Vocabula Amatoria (1966) 184: Ménage, m. The female pudendum; ‘the cuckoo’s nest’.
a.1969		‘The Cuckoo’s Nest’ in G. Logsdon Whorehouse Bells Were Ringing (1995) 233: I like a girl with the bubbies on her breast, / And a road that’s easy travelled to her cuckoo’s nest.