Sibling Rivalry

Katie was lying on her bed, scrolling on her phone, when Robert and Taylor came in to see her. She was confused because they rarely went into her room together. In fact, she figured long ago that her two step-siblings hated each other. She rarely saw them speak, and when she did watch them interact, it felt like there was an edge of rage in the room at all times.

"See stupid," Taylor said, "I told you she was in here. You just wanted her all to yourself, didn't you. Fucking ass."

"I was not," Robert said. "I was just guessing. I told you, 'I think she's gone for the day.' You're the one who is having a fucking meltdown over it."

"Whatever. You just can't be trusted. I've known that about you for ages."

"Think what you want, you dumb bitch, I don't care."

Katie lay there, with only her eyes moving from one sibling to the other. She hated it when they fought like that, but she had learned long ago that trying to get between them was fruitless, and sometimes it would make them both lash out at the negotiator. Besides, Katie figured it was probably healthy for them to get these things out of their systems. She tried her best to be pragmatic, and she figured that they needed to blow off some steam now and then to not have the issue turn into something bigger.

Katie did her best to help out both of her siblings by being a "relaxation" for them. While they were both adults, and older than Katie, she was the most mature one out of the group. She listened when both complained to her about school, or when they were having trouble with their boyfriend or girlfriend, and lastly, but certainly not least of all, she let them both use her body when they were horny. Though that was now turning into an issue, which she hadn't foreseen when she first started being fucked by her stepbrother and stepsister.

"Well, get the fuck out of here," Taylor said. "The reason I was asking was because I wanna use the little slut. And I don't want you in here, staring at us like a fucking perve. I want some peace."

"No. I'm not gonna leave you alone with her. Anytime I end up doing that for you, you fuck her for hours on and. It drives me crazy. I keep telling you, guys have different urges than women. Besides, can't you just call up Trent or whatever the fuck his name is?"

Taylor replied as she started to slip out of her clothes. "No, I can't just call 'Trey', because he's out of town with his parents this weekend. I told you that on Wednesday, so that fucking shows how much you listen. Idiot."

"Sorry that I'm not keeping tabs on every single aspect of your boring existence. You aren't the main character you make yourself out to be."

That's when Taylor got on the bed and pressed her cunt into her stepsister's mouth. Katie didn't stop her. She loved it. She had an odd urge to be dominated, and for some reason, being taken by both her sister and brother became the highlight of her days.

"Jesus, she looks good today," the brother said, his hand reaching into his shorts so he could massage his cock. "You really fucking use her, don't you?"

"God, you're so gross," Taylor said. "This is why I didn't want you in here."

"What? I'm not doing anything."

"But you're distracting me. I need to focus so I can come. I'm not some barbarian, like you."

Taylor did her best to focus on the moment, to focus on her younger stepsister's talented tongue. The element that turned her on the most when it came to her sibling was that she was so submissive. She would allow Taylor and her brother to do whatever they wanted to her. It caused Taylor to get stuck in an insane loop of fantasizing all day about dominating Katie, followed by her committing said acts, and then, leaving her be until the thoughts once again became too much to bear. Katie began to come in her sister's mouth after a few more minutes of rubbing along her lips. By this time, their brother was fully nude, stroking himself at the edge of the mattress.

"Oh, thank God, you finally finished. Scoot over."

He climbed onto Katie's backside and started to yank off the leggings she was wearing, being sure to loop his fingers into her panties so they came off as well. Then, he started pressing his cock into her wet folds.

"I didn't say I was done with her, creep."

"What the fuck, Tay. You are so slow. No, I don't care. You came just now. I saw it. Practically covered her tongue when you creamed all over it."

"That doesn't mean I'm done. Girls are different from boys, we can come more than once."

"Jesus, you've been hogging her so much that I'm pretty sure I'll come inside of her twice, too."

"Ha, you couldn't do that if you tried."

"Oh yeah? Watch me."

The brother started pumping into Katie's cunt. Plowing into her. She started crying out, unable to hold back now that her brother was digging into her tight pussy from above.

"Keep the noise down," Taylor said, pressing her clit back into her sister's mouth, stifling her cries.

"Oh, so it's cool for you to share her with me, but when it's just me, that's not allowed. Figures."

"Whatever... I'm just... Making sure Mom and Dad don't hear."

"Whatever... It's fine. I'm not greedy like some people in this family."

Robert didn't hold back as he fucked her. He put everything into his thrusts. Katie's legs started to shake, and she started to come all over his cock, and that was when he felt his balls start to contract and he emptied into his stepsister's cunt.

"Oh, wow... You came a river into her. Look."

Robert looked down, and he could see some of his spunk oozing out of his sister with each new thrust. It was thick against his shaft, dripping everywhere when he finally pulled it all the way out of her pussy.

"See, still hard."

"That doesn’t mean anything. You said you were going to come inside of her twice. Prove it."

"Yeah yeah, I'm on it."

Katie felt her insides turning to mush. She loved this. She loved every second of it. She loved how they spoke to each other and not to her. They loved how easily she made them both come. She loved how, when they did speak to her, they treated her like she was beneath them both. And most of all, she loved being their little cumslut. She found it odd that both of them had started calling her that nickname independent of the other sibling. She often wondered if that meant something. Maybe, deep down inside, Katie was a true cumslut, and the two of them were what she needed to have that brought out of her.

If anything, her brother getting the first, easy shot out of his balls made the second round all the better, for Katie, at least. He fucked her hard. His fingers dug into her hips, and he thrust in and out of her tight cunt. She felt glorious. Taylor looked on, with Katie's mouth vibrating across her own pussy.

"Yeah, that's it. Fuck her. Fuck her hard, just like that. You know what, who fucking cares whose turn it is. Katie's such a huge slut, she isn't gonna mind if we both just start fucking using her."

It was a good twenty minutes of her brother using her cum soaked cunt, but eventually he felt himself tighten up, and then he unleashed a second torrent of his seed into his sister's pussy. Then, he pulled out of her and stood beside Taylor as he pointed out how he backed up his words.

"See. told you I was gonna come inside her twice."

"Well shit, she's a fucking cum dumpster, so it wasn't like it was a fair bet or anything."

"Excuses excuses."

"You're such a fucking dweeb. Jesus. Grow up."

They continued like that as they exited Katie's room, leaving her to recover from the ordeal by herself.

L