Green’s Dictionary of Slang

tumbler n.2

[SE tumbler, a tumbril]

[late 17C–mid-19C] a cart.

In phrases

nap the flog at the tumbler (v.)

[mid–late 18C] to be whipped at the cart’s tail.

shove the tumbler (v.) (also shove the tumbler’s arse, …the flogging tumbler, shove-tumrill)

[late 17C–mid-19C] (UK Und.) to be whipped at the cart’s tail.