arselins coup, n. — Green’s Dictionary of Slang

arselins coup n.

[arse n. + sfx -ling, implying direction + SE coup, fall; thus lit. ‘falling backwards’]

sexual intercourse.

c.1800

Burns ‘Andrew an’ his Cuttie Gun’ in Merry Muses of Caledonia (1965) 148: O some delights in cuttie stoup, / And some delights in cuttie-mun, / But my delight’s an airselins coup, / Wi’ Andrew an’ his cuttie gun.

In phrases

get an arselins coup (v.)

of a woman, to have sexual intercourse.

1890–1904

Farmer & Henley Sl. and Its Analogues.