The avid pornography viewer knows that the adult film industry is expanding crystallinely into a latticework of niche kinks, like a sordid snowflake made of ménage à troises with lost cable repairmen. If you want to film a XXX adaptation of the musical 1776, A.) nobody will blink; and B.) chances are some dude in Choconut, Pennsylvania has done it first — on stilts.
So it's kind of incredible to see that perhaps the first animated blue cartoon — Eveready Harton in Buried Treasure from the late 1920s — was so dang out there. The extremely not safe for work gist of it? Eveready Harton (har har!) is a man with oversized, sentient, and detachable genitalia.
Our protagonist, who is the hybrid of Popeye and Michael Fassbender in Shame, has the hankering to canoodle with women and/or barnyard animals. Yes, the script to Eveready was seemingly written by a time-traveling Beavis and Butthead. (There is phallus fencing.)
According to animation lore, this six-minute short was made for Little Nemo in Slumberland cartoonist (and Gertie the Dinosaur animator) Winsor McCay's birthday party circa 1928-1929. In 1977, famed Disney animator Ward Kimball offered this history of the film's production:
The first porno-cartoon was made in New York. It was called "Eveready Harton" and was made in the late 20's, silent, of course-by three studios. Each one did a section of it without telling the other studios what they were doing. Studio A finished the first part and gave the last drawing to Studio B [...] Involved were Max Fleischer, Paul Terry and the Mutt and Jeff studio. They didn't see the finished product till the night of the big show. A couple of guys who were there tell me the laughter almost blew the top off the hotel where they were screening it.
You can watch the ill-fated adventures of Eveready above. It's silent, so we recommend cranking up your phonographs and blasting The Charleston until your neighbors get the vapors. Hat tip to Mikael.