Green’s Dictionary of Slang

1. one who enjoys receiving a whipping as sexual stimulation.

1673		Head Canting Academy 148: Not only the Bleeding-Cully, but the Ruff-Cully, the Dark-Cully, the Flogging-Cully, and the Fencing-Gully.
1698		N. Ward London Spy II 33: That Sober seeming Saint [...] is one of that Classis in the Black-School of Sodomy, who are call’d by Learned Students in the Science of Debauchery, Flogging-Cullies. This Unnatural Beast gives Money to these Strumpets which you see and they down with his Breeches and Scourge his Privities till they have laid his Leachery.
1725		New Canting Dict. n.p.: flogging-Cully an old Letcher, who, to stimulate himself to Venery, causes himself to be Whipp’d with Rods.
1728		W. Pattison ‘Kundumogenia’ in Poetical Works 95: Wretches, with Passions gross, and dull, By Jilts, and Bawds term’d Flogging-Cull.
1732		Harlot’s Progress 46: My bunch of rods, for Flogging-Cull / When he is jaded, dry or dull, / To modest Edm—d Cu—l I give.
1744		Machine 11: With Birchen Rod, vile, filthy, flogging Cullies.
1766		Midnight Spy (c.1929) 122: [Those] who by proficients in the science of debauchery, are termed flogging cullies. These unnatural beasts pay an exorbitant price for being socurged on the posteriors.
1773		Harris’s List of Covent-Garden Ladies 143: He is well known for the flogging cull.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue n.p.: Flogging cully, a debilitated lecher (commonly an old one) whose torpid powers require stimulating with a rod. One who hires girls to flog him on the posteriors, in order to procure an erection.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1823		‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc. 81: A flogging cull — an old lecher, not often heard of.

2. one who whips.

1732

Progress of a Rake 16: He fetch’d a Whip, of anger full, / And acted like a flogging cull.