Sisterly Ruckus~!!

Kassaz commissioned this silly little comic and wrote this silly little story to go along with it, now collected into an anthology:
https://www.fimfiction.net/story/564117/sexier-short-stories-with-particularly-pregnant-ponies

Rarity walked down the stairs leading away from her bedroom with a care she’d had to adopt for the past several months. She wanted nothing more than to return to bed with her husband, but her belly swollen with foals meant she’d need to walk to the first floor of her home before turning around regardless, lest she trip over herself and tumble down the staircase. That horrid possibility was really the only thing that stopped her from turning around immediately. She’d feel better once she fully woke up, optimistically.

Sweetie Belle stood near the end of the staircase in Rarity’s showroom, listening, and waiting. Her patience was rewarded as her muse stumbled into view, and inspiration struck quickly. Sweetie went to work immediately, assaulting the canvas with every colour she had on hoof, and even the colour she had on the brush held in her mouth. Rarity stood still for the most part—unawares of her role as model—sans some tilting and swinging back-and-forth as she tried to lose her growing headache. She stood there staring at a wall and quite annoyed that she’d left her luxurious bed, bothered by the coffee she shouldn’t drink just sitting in her pantry, upset that her foals were finally asleep while she wasn’t, and wondering how well eating breakfast weighed against getting more rest in bed. However many minutes passed while Rarity stood there with a frown on her face, not even noticing the noise behind her.

Rarity jolted to clarity as that changed. Whatever it was, it had been cold and wet, and now her foals were awake too; she knew Sweetie had spent the night. She took a deep breath, and slowly looked back with a scowl to see Sweetie Belle making a mess, which she could see running down her belly and butt in addition to feeling it seeping into her mane. It had even managed to wake up her foals, she could see by a hard kick which became many more. Sweetie Belle soon noticed and stopped her work; she had an apologetic look on her face, one that looked awfully familiar to Rarity as she slowly rotated herself and waddled that way. Sweetie stopped rearing to paint and started to step back, shrinking away while she was at it. Rarity now saw how Sweetie was transferring paint from her hooves to the nice showroom floor, and then noticed the rest of the paint already there. Sweetie was just looking at the ground now, waiting. Rarity stopped before her and took one glance at what Sweetie had put on the canvas before opening her mouth to suggest Sweetie Belle go back to their parents for the day. Thankfully, Rarity’s eyes caught up to her mouth, and she looked at the painting again. It showed Sweetie Belle dancing underneath Celestia’s sun in a field, with Rarity sitting down to watch her, hooves resting on a belly that—Rarity hated to admit—accurately took up most of her body, she told herself because of the perspective.

“I’m sorry for getting paint on you.” Sweetie’s voice was very quiet.

Rarity could only sigh. “It’s okay Sweetie.” She took on a slightly sweeter tone. “Tell me about your painting.” Sweetie looked up, at first apprehensively, but then she smiled at Rarity’s smile and walked over to rear against the easel again.

“I wanted to see if I could get a painter’s cutie-mark!” The squeak had returned to Sweetie’s voice, and she started to point out the elements of the artwork, carefully to avoid spreading any more paint. “This is me, this is you, and these are my nieces and nephews who can’t play yet!” Rarity’s smile turned into a grin at Sweetie’s enthusiasm for becoming an aunt.

“Well, I’m glad you chose a relaxing activity for me. I can’t exactly run and jump or dance like we used to do, right now.” Rarity patted her bump for emphasis, and remembered it had paint on it as she pulled her sticky hoof away. “In fact, Sweetie, I know something we can do together right now, before we have breakfast outdoors with your uncle.”

“What’s that?” Sweetie was now even more excited.

-

Rarity sighed, in delight for the first time all day. A relaxing bath was the perfect way to start her day. The room was humid and warm, leaving even the part of her jutting far out of the warm water at a comfortable temperature, given her belly was always warmer than the rest of her. She ignored how she was just a little too big to fit Sweetie Belle in with her these days; so Sweetie had taken her bath first, and was now filing Rarity’s hindhoof lazily hanging off the lip of the bathtub. Sweetie was humming a little tune to herself while she worked, and Rarity couldn’t help but close her eyes and lose herself in the moment. She thought perhaps Sweetie Belle’s cutie-mark would be in artistry after seeing that painting, but music was looking more likely as she kept listening. She couldn’t recall a single pony without a music cutie-mark who could sound so nice while merely humming. Rarity wanted to tell Sweetie Belle this, but all she could do was yawn when she opened her mouth, and soon enough she was taking a quick nap even with a belly full of active foals.

Sweetie Belle stopped her humming when she heard Rarity gently snoring. Rarity insisted she never snored, but that was a lie. She couldn’t see most of Rarity from where she sat—although in a way she was—but she could see her nieces and nephews, and she thought about the fun she’d have playing with them and helping them get their cutie-marks one day. Sweetie Belle started humming again, with an even bigger smile on her face than before.