Just a few fandom ideas.

HTTYD-1: Hiccup and Astrid, sharing an apartment while going to the same University, and teetering on the edge of entering an intimate and steamy relationship. How will they enter this relationship? A subtle nudge from a friend? A slice of drama? That is up to you.

HTTYD-2: Bit of a crossover; Hiccup and Astrid end up joining the Brotherhood; At what point they end up joining the Assassins is up to who among you guys n' gals might like to brainstorm this. As for who their adversaries might be? Plenty of HTTYD villains can fit the bill easy enough!

HTTYD-3: A world without Hiccup! Basically in this idea, Dragons are Anthros and possess hypnotic pheromones/musk along with addictive cum, and take Human women as pleasure and breeding pets, and Toothless ends up taking the HTTYD girls as his pets. How he catches them, is up to you.

Star Vs the Forces of Evil: An AU where Magic never disappeared, where Eclipsa and her husband break up, likely for a good reason with no Drama. However she is in need of a new King and she chooses Marco, gifting him with a bit of Magic in the process, a hypnotic charm to use on any girls that strike his fancy, to take as lovers. Leading to now King Marco being lovers with Eclipsa, and using this Charm. (Older Marco, obviously.)

KH-1: Basically the idea here is Sora, and Kairi on a cosmic road trip and having various misadventures, and actually spending time as a couple since in KH III we got the confirmation of that ship, yet nothing was done with it.

KH-2: A special Heartless is loosed on the Worlds, using hypnotic pheromones and addictive cum to turn various canon beauties into his pets and lovers, corrupting them one by one, possibly even with some genderbending, if anyone wants to explore that particular flavour.

KH-3: Another hypnosis themed plot! This one is starring Sora however, for a bit of a twist. Basically the concept is this; Sora gets a new Keyblade, but he isn't able to swap it out for another one and is subject to the charm/curse of the Keyblade itself. That being it turns girls in a certain radius of its' wielder into pets and lovers. More of a love potion effect than anything else. What misadventures could Sora get up to with this?

Miraculous-1: So, in this idea Alya (Rena Rouge), Marinette (Ladybug) and Adrien (Chat Noir) all decide to unmask to one another, but after some teasing and banter, things become steamy before the masks come off and long after.

Miraculous-2: Adrien has become Chat Blanc! However, free of Hawkmoth so there's no repeat of the alternate timeline however. Now corrupted, and with a hypnotic ability of his own, who knows who among the girls the Feline themed Hero might decide to put a collar on. Aside from Marinette of course. Hypnosis is kind of a required 'kink' on this one.

Ben 10: Hypnosis and harem themes. Essentially the idea is this: Ben gets a new Alien/Hybrid and goes to Gwen, (or Julie if you dislike incest) to test it out, only to find out that said Alien has hypnotic abilities, turning the girl in question into a pet/lover for Ben where upon things escalate either rapidly or gradually due to Ben actually being rather greedy and cocky when given the chance.

Rebels-1: Basic concept for this one takes place after the finale of Rebels, with Sabine and Ahsoka finding Ezra on a backwater planet in the Unknown Regions, and after an intimate reunion between Sabine and Ezra, or both girls and Ezra, depending on partner preference, they go back to Lothal. From there the plot is malleable. Let's see what we come up with!

Rebels-2: Similar to the standard reunion idea, however with hypnosis/harem themes, with Ezra using a new, hypnotic Force Power to turn Ahsoka and Sabine into his pets and lovers, before moving on to other Star Wars canon girls, using the World Between Worlds to have access to the future and past.

Ben 10-1: Basic concept with this one is Ben gets a new Alien/Hybrid, and goes to first Gwen to test it out, before finding out this creature has hypnotic abilities, resulting in the Redhead turning into his pet and lover and from there Ben, greedy as ever, begins to use this creature on other girls he knows, for example Charmcaster and Julie, though thanks to Gwen's Magic, who knows where or when he could go..!

Spyro-1: Coco, Tawna or both have a Portal related accident, and end up in Avalar or the Dragon Worlds, only to soon meet and befriend Elora, Sheila or Bianca and the pair end up bumping into a newly matured Spyro. However, it turns out Adult Dragons give off hypnotic and heat inducing pheromones, and things turn steamy between the girls and Spyro, and things go from there. This idea can branch in a bunch of ways, from Draconic greed leading to Spyro working his magic on others, to there being no Dragonesses, so instead females of other races are transformed by, and after mating with a Dragon.

Spyro-2: This is a simpler idea. Essentially the concept is Spyro makes a bet with a girl before a race, be it Coco, Elora, Tawna.. Whoever you wish, and said bet is the loser does whatever intimate activity the winner wants, only for the Dragon to win and things turn steamy.

Naruto-1: Ever read a Doujin by Sahara Wataru? This idea is essentially inspired by that, being a Hero of the Leaf Harem concept, with things starting just after the battle with Pain, or perhaps before, with Naruto's return from his training trip.


As for other fandoms? Well feel free to ask. Trust me, I know MANY.

Here's a writing sample:
Hiccup turned his gaze to the blonde for a moment and he blinked at the sight of her before blushing naturally at how scantily she seemed to dress when it was hot.. But at the same time he also shrank a little as she napped at him. "Astrid relax..! I'm almost done and we both know you get more cranky when it gets hot." They only really needed to look at his Cousin whenever he tried to flirt with her in the middle of Summer when they were younger. But still he knew she wasn't going to let him off that easily. True to his word, Hiccup was indeed almost done, and before she could snap again and probably drag him off, the auburn haired man finished his work and the AC began to work once more and he was unharmed!

Hiccup could understand her complaints however, they had been friends ever since they could walk, since his Father was friends with her parents, and ever since he lost his leg it had been almost impossible to separate them.. And he wasn't afraid to begin thinking about her romantically but he had never voiced his affection, nervous that he would upset their relationship as friends but he couldn't help but get jealous about any boyfriends she had over the years, though none seemed to last long or be that serious, save for an exception or two. Those exceptions seemed to turn out to be unsavoury after a time though, one had tried to stop contact between the blonde and Hiccup, which earned him a round house kick if he recalled correctly, and the other just broke things off.. Now, Hiccup was unsure of her latest boyfriend who was another student at the University, and had a cautious opinion about the guy, one he had voiced to Astrid.