Degradation over time

"Well it's a bit complicated obviously. Long story short, I want to utterly **** you and everything you own."

A quizzical look answers your explanation. "So... Trashing my place, I guess?"
You grin before retorting: "Well yeah, for one. But also a bit of... well a bit of everything. You'll see as time goes by, I guess. For now, I'll just hang around and forage a bit through your stuff and see if I find interesting stuff."
"Okay", a chuckling Katie replies, "have fun going through my drawers! Do you want to know where I keep my panties, or...?"
"Nah, don't worry. I'll find myself, just go on with your day for now!"

With a final smile, she goes to put some clothes on and grabs her laptop. As her well-filled pussy starts to leak on the fabric of her armchair's cushion, she asks you: "Hey can you make your cum disappear real quick so nothing gets stained?"
Her naive question ellicits a hearty laugh from you. "Oh boy, you really don't get what I meant by degradation. No, I'm not going to help you clean up in any way, shape or form, and... you know what? Forget about cleaning. Like, entirely. I don't want you to have any idea what to do with stains, or what a broom even is."
"Sounds dirty. And not the good kind of dirty, if you catch my drift", a grinning Katie answers.
"Well I find it fitting for trash to live in trash", you answer with a smile.

[- - - - - -]

As the day went by, much to your chagrin, nothing particularly interesting happened. You killed time by watching TV, raiding her fridge, and, as you said, going through her stuff. You took a quick sniff of her used panties, more out of habit than real interest. You wondered for a minute how the hell she could get freshly worn panties in a bottomless street, but ultimately decided to let paradoxical plotholes be for now; you'll solve them later, eventually. Maybe.

You were surprised to find a very modest collection of sextoys: you expected a single, non-promiscuous woman to have more than a handful of them for variety's sake, but no. Two wands and a plain rabbit were all you could find. A bit disappointed, you went back to the living room where Katie worked; your stamina well replenished, even by human standards, you wanted to use her as a living fleshlight to give her a taste of the difference between having sex and being used for sex.

Unfortunately, as you spread her legs apart, you were greeted by the sight of your own cumstains, and felt let down. Using your own sperm as a lubricant was indeed as enticing an idea as they came, but if you were to stay a bit longer, other men would probably use her, and you don't want to bathe in their fluids. This needed a pratical solution. As you grab Katie from her armchair and start lining up your cock with her cunt, you tell her: "Hey, Katie?"
"What's up, Mr. Omnipotent?", she asks as she set up her laptop on a nearby table, fully aware of your immediate intentions.
"You know that part about cleaning?"
"About what?"
"Yeah, precisely", you sigh. "Well, scratch that: you may wipe yourself after being cummed into." In a sudden flash of inspiration, you add: "In your house, one may only wipe themselves with your clothes, sheets, curtains, etc... and never with something made for wiping."
There! That should fill her house with stains in no time! Satisfied with yourself, and without further ado, you plunge yourself into her.
"Alright! I'll get a pile of clo-OOOOOOOH" is all she can muster as you suddenly penetrate her without warning. Grabbing her by the supple flesh of her hips, you make her bounce up and down on your dick as fast as you can, eager for some quick release. Coming to think about it, her vagina isn't all that different from any other one: you sigh again, halfway through your relentless thrusts. Context really does matter when it comes to getting yourself off. Simply using someone's body as a fleshy sextoy to ram through to your heart's contents has, somehow, gotten old. You'd need an audience to make it really enticing to you. Or perhaps even a participating audience. An audience made of...

In a moment of perfect synchronicity, you reach an Eureka as you unleash a long and powerful jet of jizz inside her. Your twitching member sprays her insides a bit more, making sure to paint them white, before you discard her on the armchair you took her from. She lands with a soft thump, struggling to regain composure.

"Thank you", you say, happy to have reached such a good idea.
"Yo... You're welcome", she stammers. She's probably convinced you're thanking her for the fuck. Boy is she far from the truth.

You spend the rest of the day working out the finer details of what you have in mind. For something you were dying to try out, you really didn't get into the specifics, coming to think about it. "Degrading one over time" is an exciting concept, but you could have thought about the implementation before being in the middle of it. Oh, well.

Once you're satisfied, you get to work. Normally, you'd have theatrically waved your hand to make everything happen, but this one you really want to do by hand. So you gather a few of her tools, and get to work on her front door.
"Hey, John. What are you doing?", asks Katie as she passes by.
You turn to face her, only to be met with a surprising sight: a brown stain accross her shirt. Bewildered, you forget her question and ask one in turn: "Wait what the fuck is that brown stain?"
"Oh, that? It's shit", she answers matter-of-factly.

It takes a long moment for it to all click together. Of course. You made it so she could wipe herself after being cummed into, but couldn't use tissue or toilet paper. So of course, she did the next best thing, and wiped herself with her own shirt. But wait, then that means...
"You had a shitty asshole while I was using you?!"
"Well, yeah...? I couldn't possibly have wiped before, I didn't remember how! And now that I've cleaned your sperm, I'm... not even sure how it works anymore."

This won't do. You don't want your toy to have a messy asshole - let alone a piss-soaked bush - whenever you decide to take her. Then again, you're not going to let her just wipe it. You have a way better, and way more degrading idea.
"Yeah, my bad. But you know, I think wiping doesn't actually suit you - at least wiping anything but cum."
Her trademark sarcastic grin comes up on her lips as she ripostes: "Can't make up your mind, Mr. Omnipotent?"
You'd have been unnerved by her tone if you didn't set it up yourself... and if you weren't about to do what you're about to do. Instead, you answer her grin with one of your own, and tell her: "Yeah, sorry. So, you're now able to digest human waste, and it shall taste good to you. You're flexible enough to lick your own cunt, and eager to do so whenever it's dirty. ... Actually, let's make it so you can't eat anything but human waste."
"So basically I'm a toilet?", she asks, as snarky as ever.
"Well, yeah."
"Kinda worried about quantity here. How will I get my fill each day? I mean, I can't possibly subsist on my own shit, can I?"
"Oh yeah, by the way, that's what I was doing: see the lock on your door?"
"Yeah?"
In one swift, theatrical move, you twist the screwdriver in your hands, and the lock falls down. "Well, now you don't! I'll plant signs all around your house: it's a walk-in, live-in house now!"
"So people will simply... move in without asking? Who would do that though?", she inquires, puzzled by your actions.

Wielding your power a bit for timing purpose, you make it so word have already spread at a lightning pace among the local hobo population, and thus, three of them enter the house. "Hey John", one of them says, "thanks for the invite! Gonna be so nice havin' a roof again! Hey miss."
As they salute Katie, you call them out: "Gentlemen! This is no way to address Katie! You're supposed to slap her to get her attention! It's not like she feels pain due to slaps, anyhow."
Confused and apologizing, they take turn slapping Katie. Katie keeps her grin on, thanking them for each slap. Seems like she's trying to... aggravate you by rolling with it or something? To be honest, you don't really care. Seeing her thanking people for slapping her is good enough to satisfy you.

You realize that this will all go downhill fast from here; yet you did claim it'd be "degradation over time". Perhaps you went too far? Maybe you should dial it back a bit. Or maybe you could just commit to it...?