Green’s Dictionary of Slang

camera obscura n.

[pun on Lat. camera obscura, a dark place]

(US) the buttocks, the anus.

Show quotations
[UK] press cutting in J. Ware Passing Eng. of the Victorian Era 61/2: The Arkansan walked behind the stooping darkey, swung his right boot into the air three or four times, and then sent the sole whizzing against the darkey’s camera-obscura.