Based on this image: (I can't find it.)

>Be Femanon.
>Your brother asked you to petsit this weekend which means keeping an eye on his twin pony sisters.
>Technically they’re listed as “slaves” on their town certificates, but for all intents and purposes they’re just housepets. Or at least that’s how your brother treats them. 
>Flitter and Cloud Chaser are capable of taking care of themselves for a couple of days - it’s not like they can’t help themselves to fresh water from the tap or use the bathroom - but your brother’s paranoid that they’ll leave the house and never come back.
>Perhaps ‘escape’ is the word.
>A reminder that they are indeed slaves. 
>Your brother doesn’t have a ton of money so he can’t afford a fancy home security system; you’re the next best thing to a house with doors you can lock from your phone.
>In terms of the job (that you aren’t getting paid for), you don’t really mind hanging out with the pegasus sisters. You treat them like other girls you’re forced to hang out with and they treat you pretty much the same. 
>They’re definitely more relaxed around you than your brother though.
>You know he has some kind of fucked up hots for pegasus wings and you try to keep that pushed to the back of your mind when interacting with them. You don’t even want to think about what happens when you’re not there.
>It’s about 11pm and you’ve been at the bottle since you got here after work around 8, working your way through the not-so-well-hidden cheap brandy your brother keeps in the cupboard. 
>Cloud Chaser has been stealing sips off of the commandeered bottle throughout the night and you let her get away with it. Ponies have such little constitution that it’s like watching a 15 year-old American girl have her first naughty sips of alcohol and quickly fall into a dizzy stupor. Endearing.
>Do ponies even get hangovers?
>You’re interrupted by a hiccup from Cloud Chaser.
>“Femanon, settle a debate for us?”
“What’s up?”
>The spiky-haired pegasus leans back on the beanbag chair she’s been perched in, crossing her forelegs over her exposed belly.
>“Dubs or subs?”
“What like anime?”
>“Yeah and like, animation in general.”
“Oh subs for sure. No question.”
>Flitter’s feathers ruffle up as her sister shoots her a smug look.
>“There’s nothing wrong with anime that’s been dubbed over!” she protests.
>Cloud Chaser giggles and leans further back on the beanbag chair, side eyeing the bottle of brandy on the floor next to where you’re sitting on the couch. 
>“Subbed anime is the only way to view any series. Fact.”
>Flitter, who hasn’t touched any of the alcohol is unamused.
>“I like being able to watch the animation instead of spending all my time reading captions,” she complains, ears flattened.
“Sorry Flitter, I’m with Cloud Chaser on this one. Dubs suck,” you reply, picking up the brandy bottle and pouring yourself another little glass. Down the hatch.
>“So you’d rather watch text fly by than the actual animation?”
“Well no, but like,” you take a sip from the glass, “I feel like listening to how the dialogue was originally portrayed is important. Even if you can’t understand the language you can still pick up on how the tone is used. Dubs don’t necessarily follow the tone in a similar way. They can twist the meaning.” 
>Cloud Chaser grins wider, using a hoof to push back her unruly bangs from her violet eyes to throw another victorious glance her sister’s way. 
>“See? Femanon gets it.”
>Flitter tucks her wings to her side and tosses her head.
>“Whatever. I’m allowed to think what I want.”
>“Are you though? That’s not what Master would say..”
>They call him Master? Ew...
>Flitter gasps in response, a rosy blush rising to her cheeks. 
>“Chaserrrrrr!”
>This sends Cloud Chaser into another fit of snickering as she sits up straight on the beanbag chair, mocking your brother’s voice.
>“No dubs in this house, missy! That’s a paddlin’.”
>The flush deepens.
>“Chaser, shut up!”
>The blue-haired pegasus giggles again, raising hoof at you.
>“Well Mistress, aren’t you going to discipline this naughty pony who thinks she’s allowed to have her own opinions?”
>Even though her voice is dripping in sarcasm, you can tell there’s a little bit of pain there too at the reality of their situation.
>You decide to respond with equal sarcasm and ignore the uncomfortable implications of slavery.
“Oh yeah, of course. Just come drape yourself over my knee why don’t you?”
>Flitter looks hurt and she lowers her gaze to the floor.
>Cloud Chaser, who has now giggled herself into a hiccuping fit, shrieks, “You need the hair brush first!! I’ll go - hic - get it!”
>The purple pegasus scrambles off the chair and runs towards the bathroom in a stumbling way.
>She knows you were joking, right? 
>Wait. Does your brother ACTUALLY spank his ponies with a hair brush???
>Before disgust has a chance to settle in your stomach the drunken pegasus returns, hairbrush in her muzzle.
>“Here you go,” she manages, talking around the brush in her mouth.
>“Chaser, ENOUGH,” snarls her sister, tears pricking at the corner of her eyes. “It’s not funny!”
>Ignoring this, Cloud Chaser pushes the brush into your hand that isn’t holding a glass of brandy and settles down a little ways away onto her haunches to await your response.
“Come here Flitter.”
>She raises her gaze from the floor to look at you with terror, your betrayal hitting her like a freight train.
>“Wh-what?”
>“You heard her!” prompts Cloud Chaser, poking her sister’s flank with one hoof.
>Flitter reluctantly rises to her hooves, trudging towards you, head lowered.
>“Is-is this a joke?” she whispers, eyes desperately searching your face for a punchline.
>You don’t give anything away.
“I said come here, Flitter.”
>She swallows hard and lifts her forelegs over your knee, unhappily wiggling herself into the proper spanking position. 
>You place your glass of brandy on the side table next to you and place your now free hand over her back, holding her in place. You grip the brush and bring it back, ready to send in a ferocious blow; Flitter squeezes her eyes shut in the anticipation of pain, tail trying to shield the more sensitive parts on her backside.
>What her rump receives is but a gentle tap from the brush.
“Repeat after me: subs are better than dubs.”
>Opening one eye, the pegasus shoots you a confused look.
“Come on Flitter, get with the program. Subs are better than dubs. Say it.”
>“S-subs are better than dubs?”
>Tap.
“You can do better than that!”
>Her expression softens at the realization that this is just a joke and she isn’t actually going to have her hide tanned red because of her anime preferences. 
>“Subs are better than dubs,” she admits with a giggle, lifting her tail to play along.
>Tap.
“Louder.”
>“Subs are better than dubs!”
>Tap.
“Like you mean it, Flitter.”
>“SUBS ARE BETTER THAN DUBS!”
>Now both sisters are giggling and Cloud Chaser gets off her butt to nuzzle her sister’s nose; letting her know that she was never trying to get her twin hurt, just give her a fright.  
>With a final, slightly harder tap you gently push Flitter from off your knee.
“Let that be a lesson to you.”
>The purple pegasus scampers off, rubbing her rump with a hoof.
>“You guys suck.”