You know, things get really weird when you get superpowers involved...
So the basic core of the idea is a comic book superhero/supervillain setting and I'd play a character that has a sex-based superpower. An actual character, an actual plot, an actual threat, actual plans, and an actual setting and universe - my character's main power just happens to be sex-based.
As for what kind of universe and the character himself, I had ideas and I thought I'd divide them up into their own sections.
Protected by the Justice League, Earth's champions frequently has their hands full. Fortunately they have the power to rise to the challenge. With Superman at the helm, the Justice League has a woman blessed by the gods, the fastest man alive, the world's greatest detective, the wielder of the most powerful weapon in the universe, and other men and women willing to die to keep the world turning one more day. A good thing too, with the mechanisms of Darksied, Lex Luthor, and other world breaking threats they need all the help they can get.
The Avengers, World's Mightiest Heroes - explicitly formed to handle any threat too much for any one hero to handle. Led by a living legend of Captain America, the roster filled by a man in a high tech suit of armor, two master assassins, a norse god, a couple ex-mutant terrorists, a shrinking socialite, a jade giantess, and others they face off against threats from space, from inside, from the past, and from the future.
An OC universe of our making with completely original heroes, and villains.
His name is Thomas Kruger, but he's better known to the world as the male porn star Max Holmes. He's not a household name exactly but he is moderately successful and considered one of the few porn performers with some genuine acting talent. Much to his surprise though, he's discovered that he actually has a superpower - or more specifically if he has sexual contact with someone who has a power he copies their powers for a while.
And the funny part is that he actually feels like giving the superhero thing an honest shot. And just in time too...
They say the road to hell is lined with good intentions, he's no exception. A college student has discovered that his father was Pan, a literal God from Greek Mythology. Coming into his heritage as a Panes, he tries to learn how to tap his divine heritage to make the world a better place - if how he does it is questionable at times. Soon classified as a terrorist, he's determined to help even if he has to force it...
An eco-terrorist, he fights for freedom and the environment but with questionable tactics. Among them is a power, enhanced sexual attraction pheromones but women who he's had unprotected sex with experience a compulsion to obey his verbal commands for 3 to 5 days, as long as their bodies process his semen. The compulsion may hold longer if he impregnates them. It's not flat-out mind control but as a result with a solid bareback dicking he can convert any civilian, heroine, or villainess into a fellow eco-terrorist at least temporarily. Plots ensue.