Green’s Dictionary of Slang

1. (US) the vagina.

1945

G. Legman Limerick 204: There was a young man from Berlin, / A patron of sexual sin, / He crammed the small crease / ’Twixt the legs of his niece / With a foot of his old rolling pin [Simes:DLSS].

2. (US) the cleft between the buttocks.

1971

‘B. Schade’ Happy makes it big 62: [no text] [Simes:DLSS].