Green’s Dictionary of Slang

dab n.⁴

derog. term for a woman.

1736		Bailey Dictionarium Britannicum n.p.: dab [...] a word of Contempt for a Woman.
1812		Peter Pindar Works IV 223: Their scrutinizing pow’r severe, / Discerns a vestal from a dirty dab.
1889-90		Barrère & Leland Dict. Sl., Jargon & Cant I 290/1: dab, vulgarly used in contempt for a woman, as a dirty dab, a slut, dabs being rags.

In phrases

dab it up

(Aus./UK) to cohabit.

1812		Vaux Dict. Flash Lang. (1964) 235: [T]o dab it up with a woman, is to agree to cohabit with her.
1889-90		Barrère & Leland Dict. Sl., Jargon & Cant I 290/2: dab it up, to (thieves), to cohabit with a woman.