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Multiversity	By : GeorgeGlass Category: +G through L > Gravity Falls Views: 31376 -:- Recommendations : 2 -:- Currently Reading : 1
Disclaimer: The authors of this story do not own Gravity Falls, its characters, or its giant lumberjack statue. We made no money from writing this story.

Chapter List
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Chapter 4: Power Couple
Dipper froze as he tried to process what was going on. But his brain seemed to be stuck in a loop, repeating the same information over and over.
I’m making out with Mabel. My own sister. In bed.
“Not in the mood tonight?” Mabel asked.
In the mood? Tonight? Does that mean we do this a lot? Oh, jeez…
“I…I guess not,” Dipper stammered, clumsily rolling off of her.
“It’s okay,” Mabel said gently. Then she turned on her side, putting her back against Dipper’s front. “Hold me?”
“Uh, sure,” the boy replied.
He put his arm around her awkwardly as his mind scrabbled for memories that would help him make sense of this. But his first clue came not from his brain but from his now dark-adjusted eyes, which could see that instead of two twin beds, this room was furnished with a rickety double bed, which he and Mabel currently occupied.
This visual cue brought memories: almost a month of nights together in this bed, reading, snuggling, kissing goodnight. And touching each other, in ways that a part of his mind said no brother and sister should, while another part accepted them as entirely natural. Thus cued, he remembered friends back home in Piedmont, boys who talked excitedly about their first kiss, or their first feel of a girl’s breast—always with a sister, a step sister, a cousin. It was simply expected that a boy or girl’s first love would be with a relative of the same generation.
That last thought was an abstract one, something his mind could distance itself from and consider objectively. But the memory that rushed in after it was not: another night in this bed, a night of passion and discovery, when he and Mabel gave their virginity to each other, making love sweetly, intensely, deeply. He remembered how much he wanted her: her cute face, her developing body, her hands that touched him and caressed him and grasped him tightly, her thighs that squeezed his hips and would not let go as she helped him force himself into her again and again.
With all his willpower, Dipper drove the thought from his mind. The very last thing he wanted right now was to be thinking about these sick, unnatural things.
Actually, he realized, that wasn’t quite the last thing he wanted. That would be for Mabel, lying with her back against his front, to hear his breathing quicken or—God help him—feel the erection that was trying to rise in his pajama bottoms.
It took him a very long time to fall asleep.
*          *          *
The alarm clock took him completely by surprise—a feeling Dipper never enjoyed. Somewhat enjoyable, though, was the feeling of a soft, warm body climbing onto his, settling on his lap, and gently moving forward and back, creating lovely sensations in his waking erection as the light of the morning sun shone pinkish-red through his closed eyelids.
“Rise and shine, Dipster,” Mabel said. “Although you’ve already done the ‘rise’ part,” she added with a chuckle.
Dipper’s eyes flew open, and it was all he could do to stop himself from physically throwing Mabel off his lap in horror.
“Wha-? Mabel, cut it out!” he shouted without thought.
“I know, I know,” she replied, dismounting him. “It’s hard to pee when you’ve got a boner. But I hate to waste good morning wood.” Mabel’s stomach rumbled audibly. “Hmm, I guess there are other parts of me that need filling up. I’ll see you downstairs whenever you get Boney McBonington to calm down.”
Oh my God, Dipper thought. My sister has a pet name for my wang.
He went to the bathroom, showered, and dressed, then headed downstairs to see what other craziness awaited him in this universe.
It didn’t take long to spot some of it. In the kitchen, where Grunkle Stan was cooking up some of his signature mostly-shell-free scrambled eggs, there were several clippings from the Gravity Falls Gossiper thumb-tacked or taped to the walls: “Meet Gravity Falls’ Summer Power Couple” read a headline above a photo of Dipper and Mabel standing in the doorway of the Mystery Shack, holding hands and waving to a small crowd of onlookers. “Young Love Blossoms Between Pines Twins” another title read, and the article below it showed Dipper and Mabel slow-dancing under strings of lights at some local social event.
There were other clippings, too, providing background information on the twins and candid pics of them walking hand in hand as they browsed stores downtown, or sipping sodas side by side on the Mystery Shack’s front porch. Taking all of this in, Dipper barely participated in or even heard the conversation at the breakfast table, and for once he was glad that Mabel could do enough talking for both of them.
He had only just finished shoveling the last bite of slightly crunchy eggs into his mouth when Grunkle Stan said, “All right, you two, it’s opening time. Your public’s waitin’ for ya.”
He escorted the twins to the front door of the Mystery Shack. Then he took Dipper’s hand and put it in Mabel’s before giving the boy a critical look.
“C’mon, smile, kid. Nothing attracts tourists like my happy celebrity couple.”
Through equal parts acquired memory and deduction, Dipper finally realized what was happening here. In this universe, incest between young people wasn’t just okay—it was encouraged. And the closer the relation, the more status was attached to the romance. Two cousins dating was merely cute, while a brother-sister romance was considered cool. And a love affair between twins…that was the ultimate.
Dipper managed to put on a smile as Mabel opened the door. Outside were more than two dozen tourists and several locals—including television reporter Shandra Jimenez. All of them perked up visibly as the twins emerged onto the front porch.
“Morning, everybody!” Mabel said, waving to the crowd with her free hand. “Welcome to the Mystery Shack! Come on in and check out the wonders inside!”
As the crowd began bustling toward the doors, Shandra Jimenez approached, raising her microphone. “Dipper, Mabel, is it true that you two are sharing a bed?”
The crowd uniformly went “oooooOOOOOoooh!”
Dipper felt Mabel’s elbow subtly prod his ribs. He realized that she was cuing him to answer, probably because he hadn’t yet spoken since they stepped outside.
“Well, uh,” Dipper answered, “some things in the Mystery Shack should remain a mystery.” Some in the crowd chuckled, while others groaned with disappointment at being denied any juicy details.
It occurred to Dipper to wonder why, even in this world where incest was accepted, it was considered okay for a couple of twelve-year-olds to sleep together. Thankfully, his acquired memory bank was forthcoming with the answer: The rules for sibling romances were different because such relationships were carried on under the parents’ roof—and, thus, their supervision. Which was why, when their mom and dad had taken Dipper and Mabel for a round of precautionary immunizations before sending them off to Gravity Falls, Mabel had received a shot of Depo along with the vaccines against tetanus and typhus.
Dipper and Mabel went back inside and got to work, mostly performing the same tasks they did in Dipper’s own universe. But the cleaning, organizing, and restocking were interrupted periodically by tourists wanting to take pictures of the twins—preferably holding hands, hugging adorably, or looking deep into each other’s eyes. Dipper was just grateful that so far, no one had asked them to kiss.
Shortly after the Shack opened, Wendy shambled through the door and made her way to the sales counter, her feet dragging.
“Wendy!” Stan barked. “You’re twenty minutes late!”
“Sorry,” the girl replied, eyelids drooping. “My brothers kept me up half the night.” Then she muttered, “Horny little freaks.”
“Whatever. Just get on that register,” Stan said gruffly. “The customers aren’t gonna overcharge themselves.”
Soos piped up, “Good thing I’m an only child, huh, Mr. Pines? You don’t have to worry about me getting distracted by the opposite sex.”
“I don’t worry about that ever,” Stan replied.
*          *          *
By closing time, Dipper was feeling stressed out. The constant attention from total strangers, the frequent comments about how cute he and Mabel were together and how sweet their young love was, and the little innuendos and knowing looks were all getting to him. So as soon as the Shack’s doors closed, Dipper announced that he was going for a walk.
“What?” Grunkle Stan protested. “You and Mabel gotta go to that ribbon-cutting thing tonight. Visibility’s everything, ya know.”
“Just for half an hour,” Dipper said. Before anyone else could speak, he was out the door.
He went straight into the woods, not caring about whatever might be lurking there. As soon as he was out of sight of the Mystery Shack, he looked around. Seeing no one nearby, he started talking.
“Why the heck,” he demanded, “would you send me to a reality where I’m dating Mabel? Someone I couldn’t possibly date in my own universe, even if I wanted to? Which I don’t, by the way! Is this some kind of messed-up joke you’re playing on me? ‘Hey, let’s have some fun with ol’ Dipper. He didn’t like that universe where Wendy doesn’t love him, so we’ll put him with a girl who does love him! Oh, but there’s a catch, ha ha ha! I can’t wait to see his face when he finds out who he’s kissing!’”
Dipper suddenly stopped speaking, alarmed by the sound of something like madness in his own voice. Was this place literally driving him crazy?
It also occurred to him that maybe he shouldn’t be antagonizing the only person capable of returning him to his own reality. So he took a deep breath and collected himself before he spoke again.
“Look, I’m sorry,” he said, still uncertain whether anyone was actually listening. “It’s just…I’m not sure what the point of this is. Why am I here?”
There was no reply. Although Dipper supposed that he hadn’t really expected one.
*          *          *
Later that evening, at the ribbon-cutting for Gravity Falls’ new woodpecker sanctuary (“Where woodpeckers can live and love in peace”), Dipper saw quite a few familiar faces, mostly prominent area residents.
“Daddy, this is so humiliating,” he overheard Pacifica whisper loudly to her father. “All these people are practically ignoring me. When are you going to get those Korean scientists to clone me a twin brother?”
“Sweetheart,” her father replied, “I told you what they said: There’s no guarantee that your ‘brother’ wouldn’t end up being a sexually aggressive tentacle-monster.”
Looking strangely vulnerable, Pacifica looked down and mumbled, “Would that be so bad?”
When the event was over, Grunkle Stan drove the kids back to the Shack. Exhausted from shaking hands, making conversation, and posing for photo ops, Dipper and Mabel hardly spoke during the trip. Grunkle Stan, not one for awkward silences, filled the conversational space with comments about how much business the kids were bringing in and how famous the Mystery Shack was becoming in the region thanks to “my two little lovebirds.”
When they got home, Mabel took Dipper’s hand and said, “Time for bed. G’night, Grunkle Stan.”
“‘Night, kids,” the man replied. “Don’t keep each other up too late; I’m gonna need you bright-eyed and bushy-tailed in the morning.”
They went upstairs and brushed their teeth. Dipper and his sister stood side by side in front of the mirror like they always did, and Dipper felt oddly reassured to know that in this universe, some things between him and Mabel were exactly the same.
He was soon reminded of the differences, though, when he and Mabel emerged from the bathroom and she stripped off her sweater, shirt, skirt, and training bra right in front of him. He hated himself for it, but in the moments before Mabel threw on her purple nightgown (decorated with smiling sunflowers and the phrase “Bloom, baby!”), Dipper couldn’t help but glance at her body—pale, slim, with light-brown nipples that puffed out just a little, a sign of breast development to come. Dipper felt his face grow warm, and not purely from shame. It stayed warm as he turned his back to Mabel and put on his pajamas.
“Dipper,” Mabel said, pulling her nightgown down into place and approaching him, “I know you’re not in the greatest mood tonight, but…would you rub my back?”
“Um, sure,” Dipper said, his ordinary tone belying the tumult of visceral emotions that Mabel’s request was stirring up inside him.
He sat behind her on the bed and put his hands on her shoulders. Then he began to squeeze.
“Jeez, Mabel,” he said, “you’re hard as a rock.”
As soon as the words escaped his mouth, he feared that she would come back with some sort of awful sexual innuendo. Instead, she replied, “It’s…just the usual stuff, I guess.”
He dug in with his fingers, trying to loosen up Mabel’s shoulder muscles. The girl gasped but did not say or do anything to discourage him from continuing.
Dipper didn’t like the idea of anything making Mabel this tense. He had been so caught up in how upsetting this crazy situation was that he hadn’t even considered how it might be affecting his sister. Although she was a native of this universe, and she had seemed together and cheerful when they were out in public, neither of those things necessarily meant that she was worry-free.
“So…” Dipper began, “all of this…It’s stressing you out, huh?”
Mabel took a deep breath and let it out in a long sigh.
“It’s like…” she began. “I mean, I love being with you, like this. And it’s great that people think we’re cool and stuff. It’s just…it never stops, you know?”
She sighed again. “Sometimes, I wish people didn’t know we were twins. So we could just be like everybody else.”
The gears in Dipper’s head spun as he processed the implications of Mabel’s words. His sister didn’t regret at all the romantic turn their previously typical sibling relationship had taken. Her stress was entirely the result of the attention that it brought.
“And it doesn’t help that Grunkle Stan keeps using us for publicity or whatever,” Mabel added. “I mean, I think the only reason he bought us this fourth-hand double bed is that people will be even more interested in us if they think we’re sleeping together.”
“Wow,” Dipper replied, especially because he knew that his alternate self subscribed to the same theory.
For a minute, they were silent as Dipper continued to work Mabel’s muscles like stubborn modeling clay. Mabel made little grunts, gasps, and sighs of both pain and relief. Then she turned around and faced him.
“I know I’m asking a lot from you tonight, but…could you…help me relax some more?”
Dipper’s acquired memory kicked in, and he remembered other nights when his sister had been stressed out and tense, and the way he—the other he—had helped her release that tension.
A part of his mind screamed against it, telling him that the very thought was wrong, that he should be running for the bathroom to vomit rather than giving any thought whatsoever to “helping” Mabel with her stress.
But it would help. He knew that. And his extreme discomfort at the thought of…doing that…with his own sister was offset by his desire—no, his need—to make her feel better. A need he’d had any time he saw that Mabel was feeling down, for as long as he could remember.
On top of that, he had urges of his own. And much as he tried to push them down, to ignore them, to send them back to the dark corners of his mind from which they had come, they asserted themselves more clearly and forcefully with each passing moment. This body he was in, and the mind he was sharing it with, remembered with both thought and instinct the pleasure of the flesh that they had found before with Mabel, and they wanted it again.
He closed his eyes. He would go along for the ride. He would follow the urges of his other self, to give Mabel what she needed. He was not truly in the driver’s seat, here.
It was a lie, of course. But he made himself believe it.
“Mabel,” Dipper said slowly, “whatever you need to do with me…whatever you need me to do…I’ll…I’ll do it.” He swallowed. “Always.”
She put her arms around him, and he felt her breath on his face, warm and sweet.
“I know,” she said softly. “That’s why it always helps.”
He turned off the lights, and then she kissed him. Despite being in the dark, he closed his eyes, both to concentrate on the sensation of those impossibly soft lips against his, and to help himself forget that those lips belonged to his sister.
He let her push him down on his back and move her body on top of his as she kissed him again, and again. He put his arms around her, not wanting to risk hurting her feelings by appearing unenthusiastic.
He kept his eyes closed, trying to think of someone other than his sister. His mind flashed on Wendy, but that wound was too fresh; the certain knowledge that he could never be with her would be a boner-killer. Then he thought of Tiffany Litz, a pretty, outgoing blonde girl he had admired from afar for most of the past school year. Yeah, that would work; he had long fantasized about how Tiffany’s tautly athletic and wonderfully mature body would feel against his.
His eyes still closed, he pulled her against him, kissing her more earnestly now. The thought of being in such an embrace with Tiffany was helping him get hard.
As she had that morning, she set her groin firmly on top of Dipper’s hard length and moved back and forth. Even through the two layers of his pajama bottoms and the girl’s panties, Dipper could feel the heat of her pussy on his shaft, making him even harder.
Informed and emboldened by his experience with Wendy, Dipper rolled the girl off of him and got up on his knees behind her. She took the cue and got on all fours in front of him.
Eyes still closed, Dipper fondled her small ass, enjoying the feel of her two pert globes in his hands—they were firm and springy, just the way he imagined Tiffany’s ass might feel. Then Dipper slid a hand down between her thighs and easily found her wet slit, which radiated heat he could feel several inches away.
She clearly didn’t need more foreplay; she was ready for the main event. So Dipper held her open with the fingers of one hand and guided his cock to her entrance with the other.
“Unghhhh,” she moaned as he pushed in. Dipper wasn’t even aware of what sound he was making, if any, as he entered her; he was focused entirely on the sensation of tight pussy around his length and the image of Tiffany on hands and knees before him, making sounds of pleasure as he coupled with her.
He fucked her slowly at first, holding that cute ass and helping her push back against him with each deliberate thrust. He listened to the sounds she made, too, and when he got the sense that she was ready, he sped up his thrusts.
“Mmm…nnnhhh…” she moaned, and Dipper couldn’t help but fuck her even harder at the thought of Tiffany making such sounds as he plunged his length into her again and again. And as he thrust faster and deeper, her sounds of pleasure grew longer and louder.
He gripped her ass hard now as he felt his climax approach. Now he was fucking her as hard as he possibly could, trying to get to that place where ecstasy lay.
“Oh, God, Dipper!” Mabel shouted.
“Ngggaaaahhhhh!” Dipper cried out as he was suddenly hurled over the edge and free falling in orgasmic oblivion. He barely heard Mabel’s own screams of ecstasy.
After they caught their breath, Mabel said, “That was exactly what I needed.” Then, snuggling up to him, she added, “Thanks, Bro-Bro.”
“Um, ah, you’re welcome,” Dipper stammered.
Mabel laid her head on his shoulder, and soon she was snoring softly. Dipper lay awake, staring up into the darkness.
He had tried so hard not to think about the fact that it was his own sister that he was having sex with. He had managed to turn himself on with a fantasy about another girl, getting almost all the way to orgasm by holding the image of Tiffany Litz in his mind’s eye.
But it was Mabel crying out his name that had made him come. Not just a girl’s voice, but Mabel’s voice.
And that knowledge kept him staring up at nothing for a long while, until fatigue finally reached up and dragged him down into slumber.
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Multiversity