Light shimmered on Evelyn's brown fur as she laid in the sun, enjoying it's warmth after a dip in the cool water. Raina and Jessica were nearby in the pool absorbed in a vicious splash fight. She tried to ignore the errant bits of water that kept landing on her face as she stared at the clouds rolling by, somewhat mesmerized by the shapes that formed and dissipated. Her concentration was suddenly shattered by a wave of cold water splattering against her, re-wetting the pink polka-dotted bikini she was wearing.
 
"Do you mind!?" She barked towards the feisty duo, scooting her chair farther from the line of fire.
 
"Sorry, Eve, guess I got carried away." Jessica laughed, looking around for Raina who had slipped from her view. She gasped as the small redhead breached the water behind her in a surprise attack. Before she could react, Raina had already pulled the string on her white bikini-top, causing it to fall from her ebony curves. Escaping her assailant, Jessica re-tied her bikini and lunged towards the giggling girl.
 
"Serves you right." Evelyn balked, turning her attention once again to the sky. Giant grey clouds hovered over the horizon, quickly approaching their pooltime fun. Lightning flickered within them as a low rumble filled the air. "Uhh, we better go inside, looks like a storm's coming."
 
"Aww but I was just getting started with this little monster!" Her sister whined as she climbed out of the water, Raina struggling in a bear hug, face firmly nestled between her breasts. Her captive continued to wiggle as the horse's hooves clopped on the concrete patio towards the house.
 
"Are you ever going to let her go?" Evelyn asked as she pressed her body against her sister's, pinning the young girl between them. "She's fighting awfully hard." She added as the two mare's wrapped their arms around each other.
 
"Oh, maybe eventually." Jessica replied while pushing the chestnut mare onto the sofa, "but now you're both my prisoners." She added with a cheeky grin before pressing her lips against her sister's.
 
Raina fought with all her might, head imprisoned by four soft pillows and her butt pressing against Jessica's bulge that could hardly be contained by her swim suit. She likes attention, but this was getting a little out of hand.
 
Jessica's tongue attacked Evelyn's as she tried to escape, slapping her sister's ass and grunting in disobedience. After a few minutes she was able to wrestle the inky mare off, freeing the girl in the process.
 
"Can you maybe ask me first next time you want to suffocate me between your boobs!?" Raina yelled at the duo, her face as red as her hair from the exertion and lack of oxygen.
 
"Aww honey I didn't mean to" Evelyn started before being cut off.
 
"I'm tired of you two always using me like a toy." She huffed.
 
"Well we are like, twice your size and then some. What do you expect?" Jessica added, not helping the situation before being hushed by her sister.
 
Thunder rattled the house as the storm washed over. Raina gazed out the window for a moment before getting an idea.
 
"Since we can't play outside anymore, what do you two say we have ourselves a little wager?" She mused, "You two versus me in Super Smash Sisters. If I win, you two are my slaves for the rest of the day." She added with a smirk.
 
"And if we win?" Jessica pondered.
 
"I will personally clean your entire insides, top to bottom." Raina said over her shoulder as she set the game console up.
 
The pair thought for a moment, it had been a long time since they had gotten the works, it would be nice to feel so fresh inside, and they both loved having Raina explore their guts.
 
"I'm game!" Jessica blurted out with a smile, "how 'bout you sis?"
 
"Since we have nothing better to do, why not." Evelyn added.
 
Little did they know Raina had been practicing this game for a very long time, even together they couldn't even touch her. "Victory, Red Team!" flashed on the screen as they looked at each other, knowing what they had agreed to. They were played like a fiddle.
 
Raina sat in silence, relishing the moment. She looked back and forth between her new slaves, wondering what to do first.
 
"I guess you beat us fair and square... Mistress" Evelyn said dejectedly, letting the controller fall to the ground.
 
"That character is bullshit! The controller is too small for our hands!" Jessica exclaimed.
 
Raina said nothing but slowly walked towards her insubordinate toy with a grimace. Gently she lifted a foot, placing it on the mare's crotch before pressing down firmly, soliciting a yelp of pain from the beast.
 
"You would do well to follow your sister's example." She said calmly, "you wouldn't want to lose your mistress's favor so soon, would you?"
 
Jessica looked away sheepishly, catching a small grin on her sister's lips. Never had she taken orders before, she was always the boss. Something stirred in her loins, to be commanded by this diminutive girl who was half her size, it felt... exhilarating.
 
"N-no... m-m-mistress... I wouldn't." The defiant mare stammered between grunts of pain.
 
Raina smiled and took her foot off the aching ballsack. "That's a good pet, now get on all fours." She commanded, pointing towards the carpet.
 
Jessica quickly obeyed, lest she incur more punishment. No sooner had her hands hit the floor was the redhead seated on her back with her silver mane gripped firmly in a ponytail.
 
"Giddy up, steed." Raina commanded, slapping the horse's ass. Her mount moved forward around the living room being steered by the mane. She delighted in the control, such a defiant mare following her whims. After a few rounds she steered Jessica towards her sister who was still sitting on the couch patiently awaiting orders.
 
"Spread your legs, wide." Raina commanded. Evelyn wasted no time and was holding her legs out to each side. Jessica locked eyes with Evelyn as she crawled closer, blushing at her sister's smirk. Soon her snout was pressed firmly against the polka-dotted bikini bottom, the scent of what was hidden beneath wafting into her nostrils.
 
There came a firm command accompanied by a tug on her hair, "Lick."
 
A pink tongue slid from between the mare's lips, gliding across the polka-dotted barrier. She could hear Evelyn moaning softly as it passed over sensitive areas. Raina leaned forward and hooked a finger through the bikini bottom, pulling it away, revealing Evelyn's awaiting pussy. With a firm nudge from her rider, Jessica's muzzle was buried deep in the silky folds. As she explored, her sister's moans grew louder and she could hear her mistress admiring the show.
 
"Hey Eve." Raina mentioned, grabbing the mare's attention, "You and your sister have a lot of crazy powers, I want you to tell me about any I don't already know."
 
Jessica's eyes widened, her sister wouldn't really blab, would she? She gave a pleading expression to the horse she was busy pleasuring.
 
"Well..." Evelyn started, giving an apologetic glance to the face buried in her crotch, "Jessica change size on a whim and we are both immune to digestion, as other can live inside us, we can live inside others."
 
A groan of dissatisfaction came from the ebony beauty under Raina who quickly quieted her pet.
 
"Also..." She continued, "Spending time inside our bodies has a tendency to, how do I put this, awaken abilities in others. Since you are no stranger to my gut, you can probably move objects within your digestive system if you concentrated. Maybe more."
 
"What are the limits on Jessica's size shifting?" Raina asked with a devious smile.
 
"As you see her now is roughly the upper limit, however she can shrink to the size of a banana but has never been too keen on being small." Evelyn replied between soft moans.
 
"Enough of this." The redhead commanded while dismounting, "You will shrink for me, as small as you can."
 
Jessica sat up, free to breathe clean air once more. There wasn't much she disliked more than being small, so weak and helpless. However, her mistress was waiting and she found it strangely difficult to muster any courage to say 'No'. Closing her eyes, she concentrated on being tiny. She never feels the transformation, but upon opening her eyes she was startled by the unfamiliar sight of Raina towering over her.
 
Raina scooped the tiny mare into her hands, fascinated by what she just witnessed. The miniature horse looked away bashfully, now fully exposed since her clothes don't change size with her.
 
"Aww she's so cute!" Raina said with a chuckle, fondling her new toy, "Eve, I have an assignment for you. You will put your sister up my butt." She added, eliciting a few protesting squeaks and wiggles from the mare in her hands as she passed it to her servant.
 
"Yes, mistress, anything to please you." boomed the towering beast, grinning mischievously at her sister. Sucking on Jessica like a lollipop, she waited for Raina to get into position.
 
Falling to all fours, the redhead presented her perky cheeks to Evelyn, biting her lip in anticipation. Feeling the cool saliva on her hole as Jessica's muzzle was pressed against it sent shivers up her spine. Soon to be imprisoned, her toy could do nothing but struggle in vain. Evelyn took great delight in every bit of her sister she pushed into the girl as she listened to the gasps and moans of her lover.
 
Now halfway inside, Jessica felt the hot, humid air of Raina's rectum wash over her. This smell wasn't as pleasant as Evelyn's she thought as her nostrils reflexively tried to close. As the tight ring slid over her stomach, she felt the massive hands let go causing her legs to dangle. Outside, Raina had commanded Evelyn to let go so she could try pulling her prize in herself. Slippery walls contracted around her and began tugging softly inward. As her captor practiced, the motions grew stronger until they were actually sucking her deeper inside. Slowly at first, the tight ring made it's way onto her hips. Soon it had swallowed her thick thighs, subjecting her jewels to the undulating warmth. "Gods!" She cried out to nobody as the gentle caressing excited her cock from it's sheath. With the difficult part over, Raina's anus gluttonously devoured the rest of it's meal.
 
Watching her darling sister disappear into her mistress' ass, Evelyn awaited further instruction patiently but couldn't help but rub her nipples through her bikini top.
 
This pleasure being unlike anything she had ever felt, Raina could barely keep from collapsing. Her insides writhed around the black-furred mare, feeling her curves, massaging her entire body. She let her mouth fall open and breathed heavily as she grew accustomed to the feeling. Jessica's cock was easy to feel so she paid extra attention to that region.
 
"Lay... on your back..." She panted while standing up, her slave quickly obliging. Standing over Evelyn's face, she crouched to her knees and presented her newly filled hole to the anxious mare. Without a word, Evelyn began tending to her mistress' ass, sliding her tongue in an out, briefly feeling her sister's hooves when she pressed hard enough.
 
Grinding back and forth, Raina slid her hands under Evelyn's bikini top to find two hard nipples. Squeezing them, rubbing them, she moaned loudly as her prey struggled inside and the velvet tongue explored. So absorbed in the moment, she didn't even feel the pressure building around her captive. Without warning, a fart burst from her straight into Evelyn's mouth who began coughing furiously. "I guess you can consider that payback for the car incident." Chuckled the redhead.
 
Evelyn felt strange. Something was different about that fart but she didn't know what. Her tongue slipped from Raina's depths unexpectedly, she tried to rectify this to no avail, Raina was growing larger and farther away. Glancing around the room, everything was huge, had she been shrunk like Jessica? How!?
 
"I didn't say you could stop." Raina said in an annoyed tone. Upon inspection, she was equally surprised to not see the massive beast that had been under her mere seconds ago. "Eve!? Where did you go!?" She shouted, looking desperately around the room before hearing little squeaks coming from below. Evelyn had a baffled expression as the giant picked her up. "Is this what you meant by 'awakening abilities'?" She boomed. Her question was answered with frantic gesticulations and barely audible squeaks. "Oh well." She added, "Guess I'll make the most of it."
 
Evelyn shuddered as she was thrust into her mistress' mouth, the powerful tongue having it's way with her as she too was coated in saliva. Before she knew it, her face was being pressed against Raina's asshole. Already warmed up, the hole began swallowing her with relative ease, savoring it's time with her breasts and hips. As she was pulled deeper, her body slid against her sister's until they were face to face.
"What the hell, Evelyn!? You never told me you could change size too!" Jessica blurted out angrily.
 
"I can't I swear! I think Raina's fart did something to me, maybe she can copy powers and bestow them on others?" Her sister replied.
 
"Serves you right, telling her about my least favorite ability. I have to admit, though, it's rather nice in here." The ebony mare cooed, slipping her arms around Evelyn, "Even nicer now that I have someone to suffer with me."
 
"Oh yes, this is simply torture!" Evelyn added sarcastically wrapping her legs around Jessica's hips. With some effort, Jessica was able to penetrate her sister and they locked lips and began to make love inside their mistress' rectum.
 
Feeling them move in her was incredible. As they fucked inside her, Raina began pleasuring herself. Fingers sliding up and down, in and out, she collapsed on the couch moaning in ecstasy. Wanting them deeper in her depths, she focused on the muscles once again. Breathing became difficult and she squeaked with pleasure as her undulating toys were pulled farther in. Looking down at her belly, she saw a small lump squirming with her captives. Unable to hold back any longer, seeing the bulge made by the two sisters sent waves of pleasure over her entire body. Moaning and arching her back, Raina squeezed the pair tightly with each spasm.
 
Unable to move on their own anymore, Evelyn and Jessica let the contractions of the smooth walls thrust them together. Together they grunted as orgasms swelled within them. Each cried out as their bodies were wracked with ecstasy as the ebony mare filled her chestnut counterpart with more cum than she has ever felt. Soon, a strange calm washed over the trio as they sat, panting and exhausted.
 
Raina wanted to keep them inside forever but without knowing if Evelyn would spontaneously grow to normal size again, she decided against it. Her freckled cheeks scrunched as she pushed her toys out simultaneously, stretching her tired ring. They shivered as the cool air touched their wet fur. After a few minutes of recovery, Raina took the sister's to the sink and washed them off with warm water before taking them to bed.