Comic books are often dismissed as just "for kids," but they also represent a powerful art form that attracts imaginative storytellers who are interested in writing about the entire spectrum of human behavior... even the dirty stuff. They’re not all great, but at the intersection of sex, gore, and quality you’ll find the best comics that definitely aren’t for kids.
In the Golden Age, many comics embraced sex, violence, the occult, and amorality with the tawdry enthusiasm of pulp fiction. After the advent of the Comics Code Authority in 1954, mature content was forced underground to small press publishers, making it harder for mature readers to find the adult storytelling they craved. It also led to a slew of pornographic comics bereft of plot and a strengthening of the perception that the only "acceptable" comics were those portraying facile, simplified superhero stories.
Despite these conditions, some of the comic world's best creators took leaps of faith and put out comics that explore X-rated themes, yet aren't total smut (nor splatter). In fact, these adult comic books are often masterpieces. While they aren't necessarily erotic comics, these mature comic books definitely aren't for kids.
Ironwood isn't just the mystical forest between the realms of goblins and men, it's what will be happening in your pants when you read Bill Willingham's erotic sword and sorcery romp.
Just so you know exactly what kind of comic you're in for, the first book opens with the protagonist being explicitly fellated by a centaur and, later on, said centaur gets serviced by a demon with an infinitely lengthening tongue.
As a mainstream artist, Howard Chaykin liked to push the envelope. When he struck out on his own, the result, Black Kiss, actually had to be distributed in an envelope. The hard-boiled crime comic’s graphic violence, and especially its graphic sex, were too much for its original printer. When it finally hit comic stores, it arrived in a bag so that no one could browse the pervy content without paying full price.
Anyone who did pay found a noir piece full of ladyboys, bullets, blowjobs, necrophiliacs, and vampires… yes, hard-boiled vampires (fighting over a porn from the Pope's personal stash).
New Port City falls under the rule of the villainous Bomb Queen after she explodes all her rivals and her clothes.
With nipples on the loose more often than not, she dominates the news, the government, and any man she pleases.
She has a cute cat for a sidekick, but by no means is this title meant for kids, unless you think the young ones would benefit from a dose of innuendo and charred neck stumps.
Grant Morrison claims that much of the plot of The Invisibles was told to him by aliens when he was abducted from Katmandu. It's good to know that aliens like tantric sex, cursing, and sexual magic as much as Earthlings do.
At one point, the main characters find themselves trapped inside the movie Salo, or 120 Days of Sodom, which is also definitely not for kids.
When the series faced cancellation, Morrison tried to organize a "wankathon," where the energy from the simultaneous masturbation of all his readers would save the series. It must have worked, as he was able to complete the three-volume opus.