(Written while extremely drunk. Tried to write it as a comedy, but turned out grim as hell. Enjoy.)

>Today marks the one month point that you've been in this world of brightly colored ponies.
>It also means it has been one week since you were told that there was no way back to your own world.
>The news hit you more than you liked to let on. You never were one for showing weakness, and you couldn't let that happen even now.
>Especially now, in a place that was still quite unfamiliar to you.
>Over the days, you've started caring less about what happens around you, or even to you for that matter.
>Just yesterday there was a pack of diamond dogs that tried to rob a local jewelery store. Without fear for your own safety, you somehow fought them off.
>Not even being considered a local hero for the day helped you feel any better.
>You go over this in your head as you stake out the local bakery.
>Sure, you have a slew of other problems, but there's been one you've been planning on taking care of for a day or two now.
>You're still fairly young. You still have that natural instinct in you that tells you to mate. Your hand only does so much.
>Now, while you would still prefer someone of your own species, you have to do what you can with what's available.
>Sure, you could try getting into a normal relationship, but there are too many issues with that here. Plus, this is quicker.
>There's one female in particular that you have had your eyes on for a while.
>Pink mane and fur. Cheerful, bubbly personality. Looks like nothing could bring her down.
>Just the perfect kind of pony to break in.
>You don't even stop to consider how twisted you have become.
>The two owners of the shop step out the door, hanging a "closed" sign on it before they leave.
>One important thing you know is that the Pink one lives here, despite not being related to the two bakery owners.
>Once they are far enough away, you move from your hiding spot to enact your plan.
>As you travel to the back door of the building, you start having small thoughts in the back of your head.
>What are you getting yourself into? What will come of this? What will the consequences be?
>They get shoved out by one phrase.
>You don't care.
>There's nothing that could stop you now.
>By the time your inner conflict is over, you've already picked the lock to the door in back.
>The lights are already out. You hear hoofsteps upstairs, along with some faint talking.
>Shit, is there a rouge element?
>Deciding you'll have to be a bit stealthier, you slowly creep your way to the stairs.
>Despite having hardwood flooring, the structure avoids creaking, even as you ascend the steps.
>The talking is louder now.
>"No worries, babies! Pinkie Pie will be right back!"
>Oh yeah, you forgot about the Cake family's kids.
>No wonder you didn't see them when their parents left. Pinkie Pie, as you have recently learned her name, must be taking care of them while you are gone.
>This will be easier, then.
>You hide around the corner of the hallway when you see the shadow of a pony approaching.
>She prances right past you, not even aware of your presence.
>Time to mask up.
>You slip on a ski mask you managed to knit yourself when you first got here. You needed it for some of the colder areas, but never got to use it.
>It won't be that hard to get away with this, you think. It's dark so your more revealing features are obscured a bit more, as is your face.
>You could just pin it on a diamond dog or some other bipedal creature.
>Pinkie nears the other side of the hall, turning into another room.
>Perfect.
>You dash down the hall and into the room.
>The lights are on, but with your surprisingly quick thinking, you locate the light switch and tackle the pony before she even has the chance to react.
>"WHA-"
>The both of you fall to the floor, you landing on top of her.
>"Hey, who are you anyway? Well, that's pretty rude of me to ask first, even if you did bump into me. My name is Pinkie Pie! What's your name? Also, what are you, anyways? It's hard to tell in the dark like this."
>Something tells you that she isn't the brightest bulb in the box when it comes to this stuff.
>Deciding to make yourself a bit more untraceable, you lower your voice.
"You can call me Anonymous."
>Sure, it isn't your real name, but you obviously can't tell her that.
"Sorry about bumping into you. I'm just here for some fun."
>Through the darkness, her eyes light up.
>"Really? Fun is great! What do you have in mind?"
>You try not to laugh.
"Here, I'll show you."
>Now that you've lulled her into a false sense of security, all you have to do is tie her down. Which will be difficult because you... forgot... the rope.
>You fucking dumbass. You really do only have the intelligence of a common thug.
>Oh well, those bedsheets of hers will have to do.
>Curling her mane around your hand and holding tight, you drag her over.
>"Ow! That hurts, Anon!"
>You rip the sheets and blankets off her mattress. One for the front legs, one for the back.
>The tying begins.
>Pinkie whimpers a bit.
>"I-I'm not so sure I like this game..."
>You feel it. She's getting nervous now.
"Don't worry, the fun starts soon..."
>You step back to admire your handiwork as the mare struggles on the floor while laying on her back.
>Sometimes you're pretty grateful for the knotting advice you got from your dear old dad.
>It doesn't look like she knows the full extent of what you have planned. 
>Enough waiting, you're going to dig in.
>First, you roll her onto her side to face you.
>Next, you kneel down in front of the pink pony's face.
"Alright, so here's the game."
>She looks up at you, and you quietly unzip your fly.
"The rules are simple. You suck on this, but you don't get to use your hooves."
>Pinkie looks at your rod suspiciously.
>"What is it?"
>You pause.
"...A candy stick."
>Jesus fuck, not only was that one of the stupidest lines in the book, now it feels like you're a pedo. Good going.
>"That isn't a ca-"
>You shove your dick in her mouth before you start losing your erection.
>She gags on the unexpected intrusion pushing past her tongue nearly down her throat.
>"Ggsgh..!"
>The wet warm insides of her mouth feel surprisingly good against your sensitive member as you push it in and out of her.
>In addition, her tongue is moving unpredictably around you, making the feeling twice as good as before. Must be trying to avoid tasting it.
>That certainly backfired for her.
>Speaking of backfire...
>You reach behind her, feeling her soft backside and fur as you get closer to your goal.
>Pinkie tenses up at your unwarranted touch, getting more and more uncomfortable as you reach her more intimate bits.
>As you listen to the sounds of your own sloppy thrusts, the rhythm is interrupted when you bump into a tighter patch of skin on her butt. 
>Her breath hitches as she lets out as much of a gasp as she can. Your fingers explore a second more before finding a small entrance in the middle of the area.
>Having an idea of where you are, you probe into it a bit with your first digit, getting a groan in response.
>Looks like you're a bit too far north. You'll just save that spot for later.
>And with that, you go down to where her folds are located.
>More squirms of discomfort as you cram your cock into her mouth and rub at the outside of her labia.
>"Plsh.. shtp..."
>Paying no mind to her moans, you separate her lips and go a bit deeper.
>She's still dry down there. Which is good for you, because that's always more fun. 
>For now, you'll avoid the clitoris.
>You pull your penis out of her mouth with a wet plop, and you speak.
"Having fun yet?"
>The only response is a small whine, and the beginning of a tear in her eye.
"Come on. Tell me. I don't get offended easily."
>"I... I don't like this... Can we stop?"
>Chuckling, you roll her onto her stomach, and rise her ass in the air.
"We haven't even begun. Maybe you'll change your mind in a bit here.
>Instinctively, she covers herself with her tail.
>That won't do. Not at all.
>Using a pocket knife, you cut off some of the excess bed sheet tied around her hoof and tie her tail to her leg.
>You now have full access.
>Her outer genitals are shaped quite nicely. Not too fat, but still large enough to be appealing. They maintain her pink color, only slightly darker than her coat.
>The hole above it shares the same characteristics. It's large, yet tightly shut to the point where it has many different creases extending from the small opening.
>Enough. You need to get this out of you, and it's a miracle you've made it this far without climax.
>Using your shirt, you wipe your dick dry, preparing for a tight fit.
>You grab your penis and align it with her pussy. Despite its size, you can't exactly see where the opening is, but you can hazard a guess.
>Contact is made, the mare gasps.
>"Wait, are you... No, please! Stop, I don't want to!"
>Slowly, almost agonizingly so, you push forward.
>She starts yelling, so you cover her mouth.
>Your head pushes in, meeting fairly heavy resistance along the way.
>Her body is actively rejecting you now.
>Another inch deeper.
>She jerks forward.
>You try to go deeper, but can't. 
>She lets out a heavier moan than usual.
>Push.
>No advancement, but your victim expresses a lot of pain.
>Push.
>Still nothing.
>The pony tries to launch forward, but you pull her back.
>At the same time, you thrust forward.
>You're all the way in.
>You feel the slightest bit of moisture start gathering around the base of your shaft.
>Curious, you reach down to touch where you are slightly sticking out of her.
>Knowing how hard it was to get inside, you wouldn't be surprised if...
>Rising your hand in front of your face, you realize that your guess was correct.
>Small splotches of red are on your fingertips.
>Damn, you knew this would be traumatizing for her, but you didn't know she was a first timer.
>Oh well, that isn't really your problem right now.
>You begin pumping into her, staying pretty deep for now.
>Pinkie pants and whines all the while.
>"Please stop... It hurts..."
>Eventually, her body's natural functions kick in, and she reacts to the friction.
>It becomes much easier to fuck her once she's wet.
>The pace starts picking up.
>You pull yourself out halfway, and thrust back in.
>She's crying now.
>Every time you bump your hips against her rump, you're treated to a squeak, almost akin to a baby's toy.
>Something stirs in your body.
>It's time.
>You pound her as hard as you can, listening to her voice warble as you shake her.
>The pressure builds up, and comes close to overflowing.
>Taking a cheek in each hand, you push yourself in as deep as you can and let your load out.
>At that moment, you decide to look at her face.
>Pinkie is squeezing her eyes shut as tears stream down her face. Her mouth hangs open as she breathes heavily.
>You fall back, letting your penis slid out of her. It's trying to go limp, but is only getting so far.
>This night isn't over yet.
>The mare falls onto her belly, crying quietly.
>Her current position leaves her in a perfect position to examine your accomplishment.
>A mixture of her juices and your seed is leaking out of her cunt onto the floor.
>However, as terrible as she feels right now, it doesn't look like she's been used all that much.
>A problem you must fix.
>Might as well do something during the refraction period.
>You crawl over to where Pinkie is sprawled out and grab her backside, keeping it in place under your arm.
>She stirs slightly, turning her head to you. The look on her face already displays absolute shame and misery.
>Ignoring it, you take two of your fingers and start poking at her tail hole.
>Her eyes widen at the new feeling.
>You press harder.
>She starts shaking her head, the crying becoming a bit louder now.
>"No, no, no no no nononono..."
>They push past the outer ring, causing her anus to clench around your fingers.
>"Agh!"
>You up the pressure again. Slowly, you go in deeper despite the grip on your fingers.
>Thankfully, she's clean so far despite her resemblance to a horse.
>By now, you're up to her sphincter. This part should be fun. You aren't going gently anymore.
>You shove your fingers through the tunnel, breaking through the narrow muscle unannounced.
>"Oooooohh!!"
>Quite a nice reaction. You weren't expecting something that much just from your two fingers.
>Ideas float around in your head for a while about how you could have fun with this, until you settle on one.
>You start spreading your fingers as wide as you can inside of her.
>"Stop it..! I don't think I can take it!"
>Jeez. You know it's sensitive, but you know it can't be that bad.
>Stretching further, you elect to just enjoy the sound of her moans and the contortions of her rectum.
>Not quite as reactive as her vag, but still nice to feel anyways.
>It's making your buddy downstairs jealous.
>He's back in the game. He's also pretty dry again.
>Must've wiped it off subconsciously.
>You sit her back on her belly and withdraw your fingers, savoring the sharp intake of breath Pinkie takes as you do.
>After propping her butt back up, you get on your knees and realign yourself.
>This time though, you jam your fingers back in her ass. You pry her back open, and get the first quarter or so of your meat in easily.
>Taking your fingers out, you feel as her hole slowly tightens back around you.
>Then you thrust in.
>As you do, you cover her muzzle before she can let out her yell.
>Your hand vibrates with the sound of her muffled vocalizing. 
>The sensation of her innards clenching and pushing against your wood as she tries to adjust to the foreign object feels pretty fucking good.
>Again, you start off slow, letting yourself have some time to enjoy the moment.
>Over time, you start thrusting harder with the same speed. You can only imagine what it's going to be like for her to use the bathroom tomorrow.
>Around ten minutes pass before you realize you should be getting out of here soon, so you speed up, attempting to leave as much of a lasting impression as possible in her rear.
>Soon enough, you reach your peak, and spray the inside of her colon with your cum.
>You pull out when you feel her grip on you loosen and remove your hand from her face, still wet with her tears.
>As you zip your pants back up, you use that time to watch as her slightly gaping anus slowly closes back up, dribbling out your ejaculate along the way.
>You get up and leave Pinkie's room, leaving her tied up in the middle of it in a sticky mess.