Green’s Dictionary of Slang

forewoman n.

the vagina.

1890–1904		Farmer & Henley Sl. and Its Analogues.
1980		Maledicta IV:2 (Winter) 185: The anatomical relationship of the bower of bliss and its main channel is indicated in such phrases as the front gut, foregut, forewoman, gape over the garter, lower mouth, the upright grin (except, traditionally, in China), a bit on a fork.