slough, n.² — Green’s Dictionary of Slang

slough n.²

[SE slough, a piece of muddy ground]

the vagina.

1920		in E. Cray Erotic Muse (1992) 7: Chorus: Oh, rub my tits and belly, / And slip in my slimy slough.
a.1959		in E. Cray Erotic Muse (1992) 7: Chorus: Roly, poly, tickle my hole-y, / Smell of my slimy slough. / Then drag your nuts across my guts, / I’m one of the whorey crew.