cooler, n.² — Green’s Dictionary of Slang

cooler n.²

[Fr. cul, Sp. culo, the posterior, the buttocks]

the (female) buttocks; thus phr. kiss my cooler .

1797		H.T. Potter New Dict. Cant (3 edn) 23: [no text].
1811		Lex. Balatronicum n.p.: Cooler. The backside. Kiss my cooler. Kiss my a-se. It is principally used to signify a woman’s posteriors.