When I first ran across these woodblock pictures that's what I thought, because they appeared all to have the same sort of "naughty maids on the master's day in town" ethos to the composition, sort of all rumpled satin and open-mouthed kissing. Then I surfed onto the first guy with a mister the size of his neck being fondled by a geisha. Or the "get into the most uncomfortable posture ever and I'll finger you" pictures. Whoo.
It's called Shunga! It even sounds dirty. Even really famous wonderful woodblock artists like Hiroshige who you thought only did well-respected seasonal landscapes did them, and upon further research I find they were common as, well, as Playboy magazines today!
Hooray for olden-days Japanese pornography! Hooray for skinny pale Japanese guys with funny hair cuts and ridiculously massive rods diddling skinny pale Japanese ladies holding odd household objects! Hooray for 37 disturbing shades of vulvas! Hooray for everyone's kimono being monstrously askew!