Green’s Dictionary of Slang

(orig. boxing) the posterior, the buttocks.

1890–1904		Farmer & Henley Sl. and Its Analogues.
1937–84		Partridge DSUE (1984) 256/2: ca. 1850–1900.
1997		Roger’s Profanisaurus in Viz 87 Dec. n.p.: corybungo n. Arse; backside.
2019		P. Baker Fabulosa 290/2: corybungusposterior.
2023		R. Milward Man-Eating Typewriter 28: Madame O insisted she’d [...] kicked Kiki de Montparnasse up the corybungus.