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Unexpected (a Pinecest story)	By : Edward_or_Ford Category: +G through L > Gravity Falls Views: 18897 -:- Recommendations : 0 -:- Currently Reading : 0
Disclaimer: I do not own Gravity Falls or its characters. I will not earn any money from this story.

Chapter List
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Introduction
(We aren’t just dealing with sibling incest here. Taking place over a period of several years, this story involves underage Pinecest, with pregnancy thrown in for good measure. If you will find it disturbing to read about fifteen-year-old siblings dealing with the possibility of getting ready for a baby, please do not read this!)
Despite the circumstances, this is above all a story of love, and how a young couple in an incredibly difficult situation deals with their love. I hope the characterisations are reflective of Dipper and Mabel, and that the emotions ring true.
Spring 2012
Dipper wiped his brow. Spring cleaning was hard work!
The Pines family was engaged in that age-old practice of getting rid of things they no longer needed. Seemingly every year, new “stuff” would accumulate, meaning there were older belongings that probably didn’t need to be kept. On this Saturday in April, it was the basement that needed to be tackled.
They had sorted through enough old things that had been deemed expendable, including a couple of small pieces of furniture, that it would take more than one trip in the family car to haul it away to the donation depot. Dipper’s twin sister Mabel beat him to the punch when their father asked for a volunteer to go with him to deliver the first load, so this left him at home with his mom. While she started preparations for dinner, she asked Dipper to go back to the basement to sort through one last box before the others got back.
He sulked at the added work. This wasn’t fair! He was twelve years old, and it seemed lately that he had more responsibility than Mabel. He grumbled to himself as he descended the stairs. Dipper's task was to go through the family's box of old VHS tapes of cartoon movies that the twins never watched any longer. He was to make sure there weren’t any irreplaceable home videos mixed in.
After wrestling the box loose from where it was stuck in the corner and dragging it to where he had more space, he pried open the lid and sighed at the stacks of tape boxes. One by one, he took them out to examine the titles, and to make sure the tape inside matched the box. Sure enough, they all seemed to be old Disney movies, Nick Jr. television series, and other kid’s programming. None ot these had been watched by either of the twins in years, either from lack of interest or because they’d been replaced with DVDs.
There were only about a dozen or so tapes left when Dipper noticed the bottom row of tapes were not in plastic hinged boxes like the rest, but instead were in standard cardboard sleeves. He examined the titles: “Risky Business”, “48 Hrs”, “Ferris Bueller's Day Off”, “Raging Bull”, “The Shining” … Dipper didn't recognize any of these. Someone had obviously shoved some old collection of less kid-friendly movies into the box. He thought his parents might think them worth saving, and he started gathering them into a separate pile to bring up and show his mother.
Then he picked up the last tape in the row of old films, and looked at the title: “The Blue Lagoon”. He’d never heard of this one any more than the others, but he was certainly intrigued by the cover art on the box: a photo of a young teenage boy and girl holding each other close, and both appeared to be wearing nothing more than tiny loincloths. The girl’s breasts were covered only by her hair. Dipper was feeling the familiar funny tingling in his groin he would experience anytime he saw sexual stuff on the Internet he knew he wasn’t supposed to see.
After finishing the last of the tapes and verifying there were no home movies among them, he began stacking the children's tapes back into the box for giveaway. Then he stopped, and glanced nervously at the staircase. Very quickly, Dipper emptied the box again and put the old grown-up movies back in the bottom of the box, where they would stay hidden. All except one tape. The cartoons and kids programming went into the box next, and he closed the lid.
With “The Blue Lagoon” tucked under his armpit, Dipper ascended the stairs to the main level, calling out to his mother that the box was too heavy to lift. When she replied from the kitchen to leave it for now, he swiftly dashed up to the 2nd story and to his bedroom. Carefully, he hid the tape in a dresser drawer with his clothes. Closing the drawer again, he determined to wait for an opportunity to see what was up with the curious-looking movie.
By the time the school year ended two months later, Dipper had been left alone in the house for any appreciable length of time on just three occasions. The movie was watched, not coincidentally, three times in that span.
The boy's immature hormones stirred with each viewing of the movie. The story was of two children, young cousins, tragically stranded alone on an idyllic tropical island. It started showing the cousins as prepubescent kids, but the majority of the film portrayed the kids as teenagers after several years had passed. There was little left to the viewer’s imagination as the kids were shown falling in love, discovering sex, and even having a baby together! The young actors rarely wore more than tiny garments around their waists, and often they were completely naked. Dipper was amazed that such a movie could be allowed to be made, but he certainly wasn't complaining.
The movie did more than cause arousal, making Dipper have an erection. In his imagination, he also couldn't help substituting himself and his sister into the roles of Richard and Emmaline. The dynamic of the characters was familiar: they were playmates and friends, they helped and cared for each other, and they got into disagreements and fights: all of this was just like Mabel and himself. They had a very close sibling relationship already, but Dipper felt strange about the idea, if he and Mabel were the ones stranded alone, that he could kiss his sister. Or that he could make love to her. Or that they could have a baby together! He knew it was a weird daydream, and he was ashamed of thinking about Mabel like that. But every day, and most nights, Dipper continued to dream of living like that with his twin.
Just a couple of days into summer vacation, his fourth opportunity came. His parents left for the outdoors equipment store, but didn't tell him what they were shopping for. Mabel had already gone out to play with neighborhood friends. As soon as the car had left the driveway, Dipper dashed upstairs to retrieve the tape from its hiding spot.
After putting the tape into the living room VCR, he ran back to the couch. He had left the tape queued up to the beginning of the scene where the cousins go skinny dipping together, which would lead to the part where they made love for the first time. He was enraptured, his penis already hard in his shorts, as he watched.
Then without warning, Mabel bounced through the front door. “Diiiiiiiip! I’m borrrrrrrrrrred! Everyone’s gone to do other stuff!” She turned to close the door quickly before Mittens, the family’s notoriously moody cat, could escape outdoors.
Dipper mashed the “stop” button on the remote, then launched himself to the VCR to hit eject. The machine made strained mechanical noises at it prepared to return the tape, a process seemingly requiring several hours, from the panicked boy’s perspective. By the time Mabel stepped around the corner carrying the cat, Dipper had the tape in front of his crotch, trying to appear inconspicuous, and the television was glowing bright blue.
“Whatcha watching? Some nerd thing?” Mabel asked with a bright smile.
“Uh! Uh … it’s nothing!” stammered Dipper as he turned off the TV and stepped around his sister, heading for the stairs.
“Oh! Oh! It’s … it’s nothing!!!” Mabel mocked happily in her brazen yet somehow charming style. “Come on, Bro! Show me!” she called out to him while she struggled to hold the squirming feline.
Dipper was already starting up the stairs. “It’s really nothing important, Mabel! It’s a … a documentary! It’s like a science documentary on … biology!” he shouted as he disappeared into the upstairs hallway.
“Borrrrrrring!” Mabel groused again loudly, gently dropping the cat down on the floor. “I never thought I’d wish we were still in school! Is it going to be like this all summer?” Dipper came back down the stairs, his old PlayStation Portable in hand. “Let’s do something, Dipper! Your dear sister’s dying here! It’s like we’re stuck on a desert island!” The handheld slipped from Dipper’s hands and clattered to the floor. “Hah! Butterfingers!” commented Mabel with a grin full of braces.
“Yeah …” replied Dipper, flustered. He picked up the game and looked around, wanting to redirect Mabel’s attention somewhere else. “Okay, how about … a race? You try to … get Mittens to purr before I finish a lap of Sonoma on Gran Turismo?”
Mabel scratched her chin in an exaggerated manner. “Hmm! My irresistible charms on the grumpy Mittens McMittenFace, versus your girly-gaming skills. Okay, you’re on!” She ran to pick up the cat, carrying it back to where Dipper stood, his thumbs ready. Mabel calmly started rubbing and stroking the big fuzzy cat, making little cooing sounds. Dipper shifted, looking for the signal to begin. A small evil smile broke on her face. “You waiting for something, brother?” she asked slyly as she continued petting the squirming Mittens.
“Agh! No fair!” Dipper cried out laughing, launching his Corvette from the starting line. As he drove around the twisty circuit on his game console, he also thought about how happy he was with how well he and Mabel got along. She really was a perfect sister: fun, adventurous, always had his back, and was never malicious in her teasing. He really liked being with her, and couldn’t imagine growing up without her. Weird fantasies or no weird fantasies. Not that he still wouldn’t thoroughly enjoy beating her at this little contest, he thought, as he braked hard for Turn 7 and aimed to navigate around the tricky corner.
Their parents came through the front door, loaded down with bags and bulky packages. “All right, kids, listen up! Big news!” called their father. Dipper and Mabel muttered replies distractedly.
Seconds later, their mother was taking Mittens from Mabel’s arms, while their father snatched the PSP from Dipper. Then brand new bags and packs were dropped in their arms, a new cap was plopped on Dipper’s head, and just for fun, a small dollop of sunscreen was smeared on their noses. Both of them looked up to their parents in confusion.
“You’re going to have a big adventure,” their mother told them. “You’re going up north to Oregon to spend the summer with your Great Uncle Stanford!”
The twins looked at each other uncertainly.
Autumn 2012
Mabel tried to immerse herself in knitting her new sweater. But she just wasn’t into it. She set her knitting needles aside and flopped back onto her back, allowing Waddles to nuzzle up to her from his position on much of the rest of the bed.
It had been one heckity-heck of a summer! She and Dipper had, over less than three months, been through an incredible series of amazing and terrifying adventures. A far cry from her initial desire for an epic summer romance, which seemed like such a small thing now. Instead, she’d gotten to know and love not just one, but two fantastic great uncles, made life-long friendships, seen incredible supernatural phenomena, and helped win a battle with an actual evil demon!
But every day that passed, since they arrived home in Piedmont a week prior, made the memories of what happened seem more and more unbelievable. No more quirky townsfolk, no more crazy creatures, no more magic. Just the same old school, dull friends, bland suburbia. Everything special was gone!
Well, not everything. Most special of all, she at least still had Dipper! The summer had cemented her bond with her closest compatriot and best bro ever. She could never forget how much of a part of summer Dipper had been with her. She’d always treasured how great he was, for as long as she could remember, but this summer had seen him become so much more! He was stronger, braver, cleverer, and more adorkable than ever.
It really scared her when she thought he’d be staying with Grunkle Ford after the summer, that she’d have to go back to her old life alone, trying to grow up without him. She had found the bubble Bill had made for her to be a perfect way to just deny her heartache over feeling so abandoned. But when Dipper had told her he had changed his mind, that he wanted them to grow up together after all, the relief and happiness she felt was immense.
And she felt more than that, she recalled. When Dipper had testified at his “trial” that he wanted to stay by her side, he had punctuated the point with the same “Yes. Definitely. Absolutely!” that she had used at the beginning of the summer when she wanted to find a summer boyfriend. The connection made her heart do that flittery-fluttery thing that happened when she had thought of potential romance. She realized Dipper would be perfect boyfriend material, were it not for the fact he was her brother. Mabel found, to her surprise, that she felt more saddened than disgusted by the thought.
All this made it really hard to get back into the old routine, though! Come on, schoolwork? After all that she’d seen and learned? And even worse, now it was the weekend, and there was even less to occupy herself with. Even Dipper had gone for the day with their Dad to San Francisco on an errand.
What would Dipper do if he was bored like this, she wondered to herself? Probably read yet another dumb nerd book, she answered. There’s never a lack of books! Dipper should never get bored!
But what the heck, she finally considered. There’s gotta be books in this house that aren’t terrible. Mom had used to read novels all the time, she thought. I should read one of hers. Mabel wandered out to the backyard where she found her mother watering flowers, and asked if it was okay to try reading one of her paperbacks.
Her mother turned off the hose. “Hmm, I got rid of most of my books, but I’ve still got one shelf of old novels. They’re on the bottom of the bookcase in the study. Have a look there.”
“OK thanks Mom,” Mabel replied. Returning to the house, she found the shelf in question. There were two rows of books. She randomly picked a couple, but none of them grabbed her interest. Most of the novels were random single edition books by different authors. Then she noticed a row of similar-styled books, all written by the same author: V. C. Andrews. Curious, she pulled out the first in the line and read the title. “Flowers in the Attic,” she mumbled aloud, thinking about the attic that had been her home all summer.
She flipped the book over and read the back cover synopsis. Her eyes widened as she saw that it was a story about four siblings locked in the attic of a mansion, with no one they could depend on but each other. The last two sentences took her breath away: “Chris and Cathy become all things to the twins and to each other. They cling to their love as their only hope, their only strength -- a love that is almost stronger than death.”
Mabel immediately thought of how if she were in this story, she could never have a better companion and protector than Dipper. The book was building these siblings up to be needing each other to handle a really hard challenge. Well, she and Dip had faced pretty darned challenging stuff, too! How would these siblings compare to the Mystery Twins, she wondered?
Sauntering back up to her room with the book in hand, Mabel hoped she had beat boredom, at least for a little while.
Emotional upheaval during adolescence is nothing new for thirteen-year-olds. But due to the unique events they'd experienced together, the Pines twins were feeling the effects of new hormones in a way most young teenagers would never have to.
Mabel had read a great many romance novels before, but none that had ever affected her anything like the V. C. Andrews books had. Mabel consumed all the novels on the shelf as quickly as she could, but it was the first series, “Flowers in the Attic” and its sequels, that impacted her the most. The story focused on a brother and sister who came to fall in love as they coped with terrible abuse towards them and their younger siblings at the hands of their family. Although there were all kinds of issues with their relationship, there was something so pure about the love that Chris and Cathy shared, something so right. Something perfect! Something that was just like the way she felt about Dipper, and how she knew Dipper felt about her. By the end of the second novel in the series, it had shown how that kind of love could become more, could become romantic, passionate, and unbridled. That their love could be physical. That they could be complete, together! One of these books was in her hand late at night, barely a week after she’d found the novels, when she envisioned herself and Dipper holding themselves tightly together, keeping each other strong and safe from the dark forces of the world. Their clothes would fall away and their embrace, their bond, would be even closer. She caressed and rubbed herself as she imagined her brother sliding inside her, moving lovingly within her, knowing that was where he belonged. She gasped in desperate need, thrusting a finger in and out to tickle that special spot and augment the stimulation she gave her clitoris, finally experiencing the release of the first orgasm of her life. She’d had countless more since, and every one was with Dipper first and foremost in her mind.
At the same time, Dipper had to deal with his own longing for his sister. Their adventures of the summer in Gravity Falls had been amazing, and after it was all over, he shuddered to think of all the things that had happened. Putting aside the supernatural weirdness and his hero-worship of his Great Uncles, that fact that he’d shared those thrilling months with Mabel stood out most of all. Sure, he’d been stupid every now and then: he still didn’t believe he actually considered staying behind to be some kind of apprentice, and thank god he realized what a mistake that would have been. What he remembered most were the times Mabel was hurt or in danger, when he had to protect her. After losing her for days to Bill's bubble at the end of the summer, he finally knew he would do anything, anything at all, to get her back. He would sacrifice everything for her safety and happiness! He knew this was far beyond what he had ever felt for Wendy. Where he had merely wanted Wendy, he needed Mabel! In his bedroom, about a month after starting school, he was overwhelmed with these intense thoughts, compelling him to give vigorous attention to his penis. He flexed his pelvis and stroked himself faster and harder than he ever had before, imagining in his mind that he and Mabel were in the Blue Lagoon, naked together, passionately making love on the beach. He would never forget the incredible sensation as he climaxed for the first time in his life and ejaculated all over himself and his sheets.
As much as they both knew their feelings were forbidden and should have made them feel gross, they couldn’t help it. Neither could gather the courage to admit it to their twin, and barely wanted to admit it even to themselves, but Dipper and Mabel had completely fallen in love with each other.
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Unexpected (a Pinecest story)