Green’s Dictionary of Slang

buttock v.

to have sexual intercourse; thus buttocking n., sexual intercourse.

1703

Hell Upon Earth 3: The Buttock and File, that is, such as go abroad in a good borrow’d Habit, with a pretended Maid, who catching some senseless Woodcock in their wheedling Snare, bring him home, where, after a good Treat for Buttocking, they retaliate his Favour, by diving into his Breeches for the remainder of his Cash.

In derivatives

buttocking (n.)

(Aus.) criticism.

2000

P. Temple Dead Point (2008) [ebook] Steady on [...] Man’s entitled ro give his team a bit of a buttocking.

In compounds

buttock mail (n.) [SE mail, payment, tax]

a fine imposed for fornication.

1540		D. Lyndsay Satyre of Thrie Estaits (1604) 114: I gat gude payment of my Temporall lands, My buttock-maill, my coattis, and my offrands.
1814		W. Scott Waverley II 122: D’ye think the lads wi’ the kilts will care for yere synods and yere presbyteries, and yere buttock-mail, and yere stool o’ repentance?

buttocking shop (n.) [SE shop/shop n.¹ (1)]

a brothel.

1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1862		E. de la Bédollière Londres et les Anglais 313/1: buttocking shop, mauvais lieu.

In phrases

go buttocking (v.)

to have sexual intercourse.

1890–1904

Farmer & Henley Sl. and Its Analogues.