Mabel's Plan

Disclaimer: I own neither Gravity Falls nor these twins. Allz I own is this story.

Pinecest: Don't like, don't read.

Chapter 1:

Midday light shone through the window of the Pine twin's room at the top of the Mystery Shack. None of the normal chaos or noise was echoing throughout the shack. In fact, there wasn't any sound at all on this Sunday afternoon, as Stan had taken Soos and Wendy into town for breakfast. The twins were sleeping in, so he decided not to wake them. They jumped in Stan's car and drove off to Lazy Susan's for free pancakes. Meanwhile Mabel was peeking at them leave from the twin's window. She had a plan in mind, and pretending to sleep in was step one. The next step would be trickier, but she was certain she would complete it without much trouble, so she grinned her toothy grin and set her sights on Dipper, who was still in bed, snoring lightly.

"...et...up..." said the voice. Dipper looked around in confusion. He had been hearing a distant, yet familiar voice for a few minutes now, and something weighed heavily on his chest. He knew he was dreaming, as he was currently trying to hammer a talking banana to a wall. "...t...up...ipper!" said the voice. There it was again! Dipper spun around, trying to locate the source of the voice. He scratched his head, still scanning to find the voice, until the banana cleared its throat to get his attention. "Oh! Sorry banana!" Dipper apologized, embarrassed at his negligence and continued to hammer the banana into the wall. "Dipper!" shouted the voice, which was now annoyed. He froze. That was the first thing he understood. Someone must have been trying to wake him for breakfast.

Dipper opened his eyes slowly, then shut them again against the bright light from the window. Then he realized the weight keeping him from breathing. His eyes shot open in a panic, only to see Mabel sitting on his chest, grinning her best smile. "Morning dipping sauce!" she shouted. "Uh...Mabel? Mind telling me what it is you're doing?" he grunted, still unable to breathe fully. "Oh nothing much...just a little sibling bonding time.." she said with a sort of edge to her voice that he didn't recognize nor did he like. "Mabel? I'm having a hard time breathing...so could you," he started to ask, but was cut short of the view he realized he had. He blushed as he stared straight up her skirt. She had on her usual: A red sweatshirt with a rainbow on it, a navy blueish skirt, and a pair of white panties. Which, as he could see clearly, were pulled dangerously tight, exposing a flash of pink flesh. Knowing exactly what he could see, Mabel's grin grew a bit more sinister. He was trying desperately not to look, but she had made it almost impossible. She grind-ed herself a bit forward, so her panties rode up even more. Dipper felt blood leave his head to go to his...other head. "Awwww...is my little Dipper a peeping tom?" Mabel asked with a predatory edge to her voice, "Wouldn't it be a shame if everyone knew Dipper was staring at his own sister's goods.." she slid her hand slowly over his crotch, getting quite a reaction out of him. "And getting excited by it no less..." she purred. She stared Dipper in the eyes, and he knew he was in trouble.

"So then Dipper...ready to do be my little slave?" Mabel asked, almost quivering, knowing he had no choice. "W...what are you..WHY are you doing this Mabel?! We're twins!" Dipper panicked Mabel grinned even wider. "Oh please. Why do you think I'm always with your wimpy butt. Why do you think all your attempts to get with Wendy have failed? Why do you think I talk about boys in front of you all the time?! I thought you were the smart twin..." Mabel jeered. Dipper's panic both grew and turned to curiosity "What do you mean?" he asked, leering at his sister. "Because I sabotage every chance you get with her. I talk about other boys so you would hopefully get jealous and...let's just say..territorial of me..." Mabel answered with a hint of spite, "And as for why I'm always with you, well it's simply because...I love you...I want you...I need you..." Dipper froze. He stared at her, dumbstruck. "Y...you what?" he stammered. "You heard me..." she said, her voice growing softer and a blush gracing her chipmunk cheeks. "I love you..." she whispered. Dipper's eyes went as wide as dinner plates. He tried to speak, but his lips couldn't form the words. He also didn't know how to respond. He was torn between hugging her, and whispering "I love you too," or shouting "Get off me you sicko! Never speak to me again!" He continued his mental debate, and whilst he did, Mabel surprised him by placing a finger to his lips. "Shhh..." she hushed him, "I don't want an answer now...I'll make you answer once we're done..." she added, taking on her predatory grin again. Dipper gulped.

"Now Dipper, I want you to kiss me," Mabel stated blatantly. Dipper's eyes went wide again, and he shook his head, still unable to form words. Mabel looked disappointed. "Oh well...I was hoping to not have had to resort to this..." she said, placing her hands on his arms to pin him down. She then butt-bounced up and down on his chest, taking his wind out. 'She sure has gotten a big butt!' Dipper thought, gritting his teeth. When the twins both turned 17, Dipper filled out with moderate muscle almost overnight, and he grew almost a head taller than Mabel. He was still mentally a wimp, but he could easily overpower anyone, short of Wendy's dad. Mabel on the other hand, filled out where it counted most. She gained a bit of weight, and had soft, supple skin. She was almost a D-cup, and they were as perky as she was. Her butt had become as plump as her chipmunk cheeks, and she had a graceful air that had never been there before. Her hips became wide and spongy, and whether Dipper wanted to admit it or not, he caught himself staring every now and again.

Mabel continued bouncing on him, not allowing him to recover his breath. "C'mon, you know you want to," she cooed. She went from bouncing to grinding lightly. Dipper blushed as he felt her butt rubbing against him, and she knew he was about to break. "A...alright! I'll...do it..." he croaked. She grinned wider, and leaned forward towards his face. She perked her lips out, batting her lashes, inviting him in. He reluctantly leaned in, squeezing his eyes shut. She took hold of his head and brought him in suddenly, and their lips met. Fireworks exploded behind Mabel's eyes, sending electricity down her spine. Dipper, much to his own surprise, had the same reaction, and before long, he too was getting into the kiss more and more. Dipper eventually noticed Mabel was still grinding against him, but in a more loving manner. Mabel reluctantly broke the kiss once they needed to breathe, and they both stared at each other, panting and blushing furiously.

"Best first kiss a girl could ask for..." Mabel stated dreamily. "Y...yeah yeah. You got what you wanted right? Will you let me go now?" Dipper asked. "Oh no," Mabel said with a laugh, "Not until you're my obedient little slave..." Dipper gulped even louder this time. He had never known his sister to be like this. "What's wrong with you? Are you possessed by a ghost or something?" Dipper asked cautiously. "No," Mabel stated plainly, "Just tired of waiting for you to realize that we are meant for each other, so I'm just...speeding up the process." Dipper looked her in the eyes, and realized there was no getting out of this, so he might as well confess. "Mabel I do love you. But we're twins! We can't be together even if we wanted to." he said softly. "But that's just it!" Mabel cried, "It's forbidden, and that's what makes it so special. We'll think of a way Dipper, I promise." She had tears of joy in her eyes, knowing not only that Dipper loved her back, but that they had a chance. "Mabel...are you sure you want me of all people? I'm nothing special..." he said, looking at the floor. Mabel stared at him for a few moments, then lightly smacked him. "W...what was that for!?" he shouted. She placed a finger against his lips again. She brushed back his hair, and kissed him softly on his birthmark. The one he hated showing people. He flinched by this show of affection, and not knowing what else to do, wiggled his arms free, and wrapped them around his sister. Mabel snuggled close to him, and they stayed like this for several minutes, neither wanting to let go.

Finally, it was Mabel who broke the silence. "Listen, I don't really want you to be my slave...that was just something I read. 'Wimpy guys like to be dominated' or something like that..." she moped. Dipper smiled awkwardly. "It's...ok I guess..." he said. He looked up into her soulful, hazelnut-chocolate brown eyes. Sometimes he swears he catches glimpses of green, but it might just be his imagination. "You know you have beautiful eyes..." he said, accidentally saying his thoughts. Mabel blushed, and socked him in the arm. "Don't start with all that mushy stuff just yet..." she said without meeting his eyes. He laughed, and sat up, sliding Mabel off of his chest gently. "So, how are we going to do this?" Dipper asked. Mabel thought hard for a few seconds, then suggested, "Once we turn 18, we can move out together. And we can live in our own place, live by our own rules, and maybe get married in a state where it isn't illegal." She poked him gently, showing a slight blush. "They even have shots now that can make it so our children won't be inbred. We won't have to tell anyone we're twins. It can work...I just know it can." she said, trying to assure herself more than anything. Dipper draped an arm across her shoulder. "I believe it can. But we're going to have to keep it a secret from everyone until then." he said. "Who says anyone has to know?" Mabel asked. Dipper thought about this, then agreed. "Yeah, I guess you're right. Much easier that way." They hugged, both excited and impatient until they could follow through with their plan.

I know I know, got a bit quick to the point at the end there, but I have a problem with leaving my work halfway done for a while, then trying to pick up where I left off. Also, some things I refuse to back-story due to my habit of never returning to the main subject. Just enjoy the story, or don't. your choice. Next chapter I hope to cover more of their past, but maybe not. Who knows. Anyways, thanks for reading.