From The Art and Popular Culture Encyclopedia
Tentacled creatures have appeared in Japanese erotica since the Edo period; among the most famous of the early instances (and perhaps the first) is a Hokusai woodcut called The Dream of the Fisherman's Wife, depicting a woman entwined and sexually molested by a pair of octopuses. Another antecedent in Western art is La Pieuvre by Félicien Rops.
Tentacle eroticism has become popular in contemporary Japanese hentai and ero guro titles, where various tentacled monsters violently rape or otherwise impale young women (or, less commonly, men). The best-known title in the "genre" is the 1987 title Urotsukidoji.
The genre supposedly exists because of Japanese censorship regulations which prohibit the depiction of the penis but apparently do not prohibit showing sexual penetration by a tentacle or similar (often robotic) appendage.
- The Dream of the Fisherman's Wife (1820), by Hokusai
- Frontispiece by Fernand Khnopff to Joséphin Péladan’s Istar (1888)
- La Pieuvre/Octopus ()- Félicien Rops