[Copied from https://pastebin.com/SskmUqtk]

>It was a fresh Sunday morning, and you'd just given Blocky her usual weekend bath.
>You finished showering a bit early, so you were actually able to meet Blocky in the laundry room while she washed her outfit.
>"Hello, Master!~" she chirped, a cheery smile spread across her face.
>Her hooves wiped away at the plate bra, the polish doing its work and making that thing sparkle like no other.
>*BZZZZZZZZT!*
>"Oh! There's my skirt!"
>The little pony opened up the dryer, retrieving that fine, silk cloth you loved having around your feet.
>She unraveled the skirt, hugging it a bit against her face as she enjoyed its warmth.
>"That always feels so nice!"
>After, Blocky attached the skirt back onto the panties and held it and the rest of the outfit up to you.
>"Ready to suit back up!"
>You gave it a look, pondering to yourself.
>The shining metal bra invited you to grab it with its splendor.
>But you felt a little different today.
"Actually Blocky..." you trailed off. "...how about you just leave it on top of the washing machine?"
>Blocky was flabbergasted.
>"Really? I don't have to wear it today?"
"Yeah...yeah, go ahead and keep it off for the rest of the day."
>Blocky's face was a mixture of perplexed and eager.
>"Sure! ...I guess!"
>The pony trotted out of the laundry room, humming to herself as she did.
>That left you alone with the outfit.
>You gazed at it a bit more, trying to remember how long ago it was that you'd even gotten that thing.
>If you remembered right, it was some kind of collector's memorabilia you'd gotten from some distant uncle you weren't familiar with.
>Through some legal process you didn't understand and a complex inheritance bout you weren't even aware of, you got some of this uncle's collector stuff when he passed away.
>You weren't really into the movies they were from (Space Balls or something?), so you'd kind of shelved them. At some point they'd probably be worth a good chunk of change anyways.
>It was only the fourth or fifth day Blocky was here that you decided to make her wear it.
>"W-where are you taking me, Master?"
>You and her made your ways to your bedroom.
>It was just today that you'd remembered that outfit you'd gotten.
>As you were still green in terms of this slave-owner deal, you figured to better get yourself into the mindset, you should constantly remind yourself that she was your slave.
>What better way to do that than to dress her up as one?
"Just keep following me, Blocky."
>Once you arrived, you directed her to the closet, and she went over and opened it without hesitation.
>"What am I looking for?"
"There's a box in there with 'collector stuff' written on it. I'd like you to bring that out."
>At least your commanding tone was getting better.
>Her hooves fiddled about in the closet, the rustling of cardboard and clothes being the only noise heard in the room.
>Eventually, she pulled out a big box with a grunt, the exact words you said written on its side.
"Good girl."
>Slather it on, Anon.
>Blocky looked up at you, expecting another command.
>Seemed she only really thought she'd be retrieving the box, but not opening it.
>Well, that was fair. Only you knew what you wanted out of it anyways.
>Wordlessly, you sat on the bed and flipped open the top of the box, several pieces of collector's items greeting your eyes.
>There was just one that you wanted, though, and it was fairly visible.
>You couldn't miss that shiny gleam, after all.
>Grabbing it from the bottom of the skirt, you pulled out the whole pile: bra, panties, collar, and braid.
>You grabbed the bra and panty combo and presented them to Blocky.
"I want you to wear this."
>You audibly heard her gulp as she stared at the outfit, wide-eyed.
>"Th-that looks like..."
"Something a slave girl would wear? Yeah, I know."
>You didn't really need to be familiar with the series this thing was from to get the idea.
>Blocky instantly knew, so it seemed even Equestrians had some understanding of the extent slavery could reach.
>Checking the straps on both the bra and panties, you were relieved to learn that they were adjustable.
>She seemed a little bigger than a kid, so hopefully this thing could go down to that kind of size.
"On your hinds."
>Blocky did as she was told, her reddened face turned away from yours.
>You started by fastening the panties together on her pelvis, the skirt hitting the ground as it unfolded.
>Nice fit!
>A bit too nice...
>You had made sure the skirt didn't go over her tail, and odd as it was to try that, it managed to work out.
>The back of the panties sat comfortably just below her tail dock, covering her nethers while still fitting around her just fine.
>Next came the bra.
>The straps went on her back, and you tightened them until the bra fit snugly on Blocky's chest.
>"Wh-what is this used for, Master?"
>It was a fair question, considering ponies didn't have tits.
>Well, at least on their chest.
"It's for covering up some parts of human girls. You don't have those parts, but I'm still going to put it on you, Blocky."
>"O-okay."
>The braid would be an interesting experience.
>You Googled some slave girl hairstyle on a whim and found girls dressed just like Blocky.
>Weird, but you'd roll with it.
>Your hands moved to Blocky's mane, and you started by bunching up the back of it.
>Fumbling a bit with the braid in your other hand, you managed to clump it on her mane.
>Checking the reference and then Blocky, the bunched up hair she had was...good enough.
>You'd probably get better at this the more she had it done.
>Finally, the collar was clamped onto her tender little neck, with a small knob mechanism built in to keep it locked.
>The chain attached seemed to be more cosmetic than practical based on its miniscule size, but hey, maybe it'd find some use.
>Facing Blocky, your eyes scanned her now-costumed form.
>"H-how do I look, M-Master?"
>She was quivering a bit as she spoke, and while her face was forward now, her eyes still averted yours.
>There was one part of her your eyes stopped on.
>This wasn't something you said often, but you MAY have had a thing for tummies.
>And this outfit?
>It made sure it was the only thing not covered on her torso.
>That bra actually had some use after all.
>F-fuck, she had a cute little belly, too.
>A nice, lean figure with a small, pudgy roundness at the bottom.
>Was it right to sexualize a pony?
>You never really got those dudes who were into them, but right now your dick did not care at all.
>"M-master?"
>She crossed her front hooves together bashfully, covering up that nice tummy of hers.
>It was enough to bring you back to the real world.
>Holy Hell, that was a powerful asset she had.
"You look uh...you look great, Blocky," you stammered out.
>"O-oh, thank you, Master."
>She took the compliment as an indication to get back on all-fours.
>One thing was for sure after today: This slave outfit thing was probably the best decision you've made since owning Blocky.
>And it really was.
>As you looked down at this outfit in the present day, it was weird how this one collectible item turned out to be a real game-changer for your slave-owning experience.
>Would Blocky ever catch on that you just REALLY liked her belly?
>Granted, that wasn't the only part of why she was still ordered to wear this thing, but still.
>Even if she did learn, would she care?
>The belly rubs, once she stopped getting tickled, seemed to relax her, so she wouldn't have any real reason to complain, right?
>It was a little weird, but it'd probably be even weirder if she learned.
>It may be best to just not say, and that's that.
>You left the outfit in the laundry room, but she'd come back and wear it tomorrow.
>For some reason, you felt like she enjoyed it.
>Wouldn't it be funny if she did?
>You chuckled to yourself as you went on with your day.
>Blocky, outfit or otherwise, remained at your beck and call.
>What a good girl.