Pipp Petals felt like a new pony. She'd just come back from the spa and was looking forward to a bit of beauty sleep.

That possibility vanished when she opened her bedroom door to find Zipp mounted on her bed… with a giant dildo strapped to her crotch. "Oh my—" she stammered, her eyes fixed on Zipp's temporary appendage. "Where did you even get that, Zipp?"

"At the sex shop, duh!" Zipp was quick to reply. "Turns out, being a princess gets you toys like this, even if you're underage." Zipp punctuated that by shaking her hips. The tip of the dildo bobbed in her vision, drawing Pipp's incredulous gaze. A worried expression crossed Pipp's features as she looked between her sister's face and the giant dildo hanging under barrel.

Zipp sensed her worry. "We hardly ever see each other, Pipp. I just… I wanted to share a little time, you know? Draw closer together as sisters."

Pipp inwardly cringed at the idea of letting her sister fuck her with an object that size in the name of becoming closer. That thing… it's got to be reaching up to her chest! Pipp thought. And it's as wide as my hoof! At the same time, though, she didn't want to let Zipp down. Pipp was touched by the idea that Zipp wanted to get closer to her, even if she was going about it the wrong way, but she didn't want to rebuff Zipp.

"Listen, we'll take it slow, alright? It'll be fun. I promise!" Zipp said, her voice full of hope.

"But I don't want to lose my virginity to that… that thing!"

"Relax—it's not a real penis. You won't technically lose your virginity, right?"

Pipp sighed, unable to come up with a response she thought would get through to Zipp. "I mean… I guess not."

"Then whaddaya say? You wanna try it out with me?"

Even though Pipp was still uncertain about the idea of getting rutted by her own sister, she gave a slight nod. "O-okay."

"Great!" Zipp was positively glowing, the grin on her face stretching from ear to ear. "So, uh, you wanna just lay yourself on the bed there?"

Pipp complied, instinctually laying her front half on her bed with her forelegs tucked under her and her hind legs braced against the floor. Zipp stepped up behind her and placed her forehooves on Pipp's hindquarters.

Pipp felt the dildo slide up under her barrel until it hit the bed and tried to prepare herself to get rutted by her own sister, speared on the end of a big rubber dong, but nothing could prepare her the feeling of the wide rubber flare pushing up against her entrance. Zipp bent further forward, placing more weight on Pipp's back. "You ready for this?" Zipp whispered into Pipp's ear.

Biting her lip, Pipp said a final goodbye to her dignity—and her virginity—and gave a slow nod.

Pipp felt the pressure on her backside ramping up as Zipp began pushing the dildo against her, the tip mashing into her entrance. She grimaced under the strain the flare of the dildo was placing on her labia, the stretching sensation bordering on painful. Still, she persevered, if only to make her sister happy.

The flared tip shot through Pipp's entrance, making her cry out as it was carried past her hymen and halfway up her virginal canal by the force Zipp had put into her initial thrust. Pipp involuntarily clenched down on the intruder because of the pain, stopping Zipp from immediately bottoming out in her. She knew she'd never be able to take the entire thing, but she knew Zipp was going to force her to try.

Zipp laid down on her sister's back, pushing her further into the bed with her weight. Pipp let loose a long moan as she felt the dildo's hoof-width flare drag backward past her walls before grimacing again as it began to stretch out her labia once more.

Just before the dildo fell out of her completely, Zipp declared, "Here it comes again!" She shoved her hips forward, sending the rubber length surging into her sister's pussy again and milking an animalistic groan from her. Pipp felt even fuller than before, leaving her barely able to think straight. She was beginning to feel increasingly wet down there, and the dildo slid out of her again with barely any resistance.

"See?" Zipp said. "I knew this'd be fun for us!"

"Y—h-haah, y-yeah," Pipp managed to get out without looking back as Zipp pulled out for a third thrust. Pipp wished she'd been more stalwart in her protests against that assessment before the whole ordeal began. This time, Zipp pushed back in sooner and pulled out almost immediately. Gradually, she worked herself into a rhythm, rutting her sister with long strokes of her rubber cock, her athletic hips more than enough to counteract Pipp's tightness.

With each thrust, the dildo's medial ring got closer to Pipp's pussylips and the head got closer to her cervix. The more she was stuffed, the louder Pipp became, her gasps and moans increasing in volume every time the dildo went deeper into her.

Panic and disbelief had a stranglehold on Pipp. How her sister had gotten it into her head that an incestuous rutting would let them grow closer as sisters was completely beyond her, and she was seriously regretting agreeing to participate. The only time she'd felt more embarrassed was when she'd accidentally posted a picture of herself without makeup on all her social media accounts.

Pipp yelped as a thicker part of her sister's dildo bumped into her labia. She absolutely stuffed with rubber cock, and yet her sister was insisting on burying more into her, grinding the dildo against her pussy with motions of her hips. Finally, it was too much. "Z-Zipp!" Pipp cried out. "Puh-hnnguh, pleeease stooop!"

Zipp froze. "What's wrong?"

"I… I don't want this," Pipp whimpered, tears appearing in her eyes. "G-get that th-thing out of m-me." She gave a high-pitched whine as her sister began to pull her hips back.
"You didn't want this?" Zipp asked, a clear nervousness in her voice. "What do you mean 'this'?"

Pipp squeaked and buried her face in her hooves as the flared end of the dildo passed through her lower lips. "You p-putting it ins-side me." She was openly weeping now. "I… I was waiting for the right colt." She looked back at Zipp with her tear-streaked face. Zipp recoiled. "You know I love you. I'm your sister! Why didn't y-you just say you wanted to be—" Pipp let loose a sob. "C-c-closer?" She buried her face back in her hooves and folded her ears back.

"I'm so sorry, Pipp," Zipp said, though Pipp barely registered her apology. "I… I did want to be closer, but I just… I didn't know how to ask!"

My own sister just raped me, Pipp thought, pressing her face into her hooves and sobbing again. I just got raped by my own sister! She'd never felt so ashamed, or so depraved.

"I… I'm sorry," Zipp said again.

"Just… just go away," Pipp sobbed, her voice muffled with her face buried in the bedcovers. "Go away and l-leave me alone."

Zipp ran from the room, the rubber cock still swinging between her legs and dripping a trail of Pipp's juices to the floor.

There was no sleeping that night, or the next. Nonetheless, Pipp secluded herself in her room. She shook constantly, her voice coming in stutters when she dared to speak at all. Her mother was getting nervous, but so far hadn't intervened. The memory of Zipp violating her ran through her head every time her thoughts turned to her sister.

One thing was for certain: Their relationship would likely never regrow. Pipp regretted that, but she just couldn't bring herself to see her sister the same way she had before.

Author's Note

Please don't hesitate to leave a comment, and, if you want me to write more stories like this, message me on Discord at Arkadios#8775!