Green’s Dictionary of Slang

sharp and blunt n.

the vagina.

1890–1904		Farmer & Henley Sl. and Its Analogues.
1978		Maledicta II:1+2 (Summer/Winter) 117: Mr. Aylwin has a two-page section on ‘Vulgarity.’ [...] To Berkeley Hunt, however, he is able to add these other words for cunt, though he mixes up the terms used to describe female anatomy and those used only as insults (stupid berk): gasp & grunt, growl & grunt, Joe Hunt, sharp & blunt.

In phrases

have a bit of sharp and blunt (v.) (also do a bit of sharp and blunt)

of a man, to have sexual intercourse.

1890–1904		Farmer & Henley Sl. and Its Analogues.
1896		Farmer Vocabula Amatoria (1966) 106: Enfiler. To copulate; ‘to do a bit of sharp and blunt’.