Green’s Dictionary of Slang

buttock v.

[buttock n.]

[18C] to have sexual intercourse; thus buttocking n., sexual intercourse.

In derivatives

buttocking (n.)

[2000s] (Aus.) criticism.

In compounds

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

[16C–early 19C] a fine imposed for fornication.

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

[early 19C] a brothel.

In phrases

go buttocking (v.)

[18C] to have sexual intercourse.