We already knew about the art historical precedents of tentacle hentai, but these examples of erotic Japanese and Indian art in the inventory of a Seattle gallery - featuring such contemporary fetish favorites as flogging, dildo masks, and spectrophilia - were a revelation.

Japanese Shunga and Other Erotica (essay and reproductions @ Greg Kucera Gallery, Seattle - via Geisha Asobi)
See also: "Japanese Erotic Prints: Shunga by Harunobu and Koryusai" and "Sex and the Floating World: Erotic Images in Japan, 1700-1820"(Amazon)
Previously: Hardcore Bondage Hentai, Spectrophilia, "Gay Erotic Art in Japan"