bumbazine, n. — Green’s Dictionary of Slang

bumbazine n.

also bombazine

[? pun on bum n.¹ (1) + SE bombasine, ‘a twilled or corded dress-material, composed of silk and worsted; sometimes also of cotton and worsted, or of worsted alone. In black the material is much used in mourning’ (OED); note Walt Kelly’s short-lived cartoon strip Bumbazine and Albert, featuring a young black boy who talks to animals, created in 1943 and a precursor to Pogo]

(US) the buttocks.

1845		H.C. Lewis Works 91: It was bombazine and reminded her by the first syllable of the seat of ‘Cupping on the Sternum.’ [HDAS].
1867		in Somers Sport in N.O. 161: [A hard punch sent Turner] to grass on his bumbazine [HDAS].