Green’s Dictionary of Slang

dab n.³

a bed.

1812		Vaux Vocab. of the Flash Lang.
1821		Egan Life in London (1869) 311: We kept it up till very long after the Regulars had been tucked up in their dabs.
1833		‘The Beak and Trap to Roost are Gone’ in Swell!!! or, Slap-Up Chaunter 49: Nor peck nor booze too have we got, / Nor ken nor dab have we.
1840		Flash Mirror 4: The Flea Trap [...] Very good dabbs may be had here [...] consisting of an upper slasher, a pair of flesh receivers, and a straw swetter.
1846		Swell’s Night Guide 117/2: Dab, [...] a bed.
1847		[A. Harris] (con. 1820s) Settlers & Convicts 39: Our entertainer [...] began to ‘make the dab’.
1855		Yokel’s Preceptor 29: Dab, A bed.
1873		Sl. Dict.
1894		Truth (Sydney) 19 Feb. 2/8: To speak of bed [...] is ‘dab,’ ‘doss’, [...] ‘bug walk’.

In phrases

dab it up (with) (v.)

of a man and woman, to cohabit.

1812		Vaux Vocab. of the Flash Lang.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1890–1904		Farmer & Henley Sl. and Its Analogues.