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Fistbump (a Pinecest story)	By : Edward_or_Ford Category: +G through L > Gravity Falls Views: 13063 -:- Recommendations : 1 -:- Currently Reading : 0
Disclaimer: I do not own Gravity Falls or its characters. I will not earn any money from this story.

Chapter List
- 7
- 8
- 9
Mabel took Dipper’s face in her hands as he was kissing her neck. She brought it up to hers and they kissed deeply, then she broke the kiss slowly and looked directly into his eyes. “I need you to make love to me!” she said quietly, but firmly.
Most boys would, of course, immediately scramble between a girl’s legs if they heard those words. As had been already established, though, Dipper was not most boys.
His eyes widened, and he swallowed. Even with all that had just happened, what they had already explored together, the suggestion that they “go all the way” stopped him in his tracks. He hadn’t imagined when he awoke that morning that he might no longer be a virgin before the end of the day, let alone that the girl that he would first have sex with would be his sister! He couldn’t just go along with Mabel’s plea: shouldn’t they talk about this? He was positive he was in love with her, but still. There would be no going back to the way things were. There would be no way to unring this bell.
“Mabel … wait … are you sure … I’m just …” Dipper stammered.
Mabel gazed in his eyes. “Yes, Dipper, I’m sure. I made up my mind a while back,” not mentioning that “a while” was less than a half hour previous.
“But … you could get pregnant! We haven’t got anything for protection!” Dipper was aware that Mabel had started her periods earlier that year, and what that could mean to a girl having unprotected sex.
“I just had my period three days ago. I’m perfectly safe, Dipper!” Mabel told him quickly.
Dipper had already thought of another objection to be considered. “But … isn’t it supposed to … hurt you the first time … ? I don’t want to hurt you!”
“You mean you don’t want to bust my cherry?” Mabel was getting impatient that Dipper wanted to debate this.
“Well … yeah, I guess if … that’s what hurts?” Dipper was not fully educated, but he did have Mabel’s interests in mind.
“Dipper, you know my hairbrush?” Dipper nodded dumbly. “Well, it’s been used for a lot more that brushing hair and as a fake microphone!” Mabel barely waited for Dipper’s expression to register understanding. “It won’t be painful for me. I want this Dipper! Please!”
There was one card left, and Dipper had to play it. He didn’t want either of them to be regretful. He drew a deep breath.
“Mabel, please … it is not that I don’t want to do this but … are we sure this is right? I mean … our age, for starters. Are we … are we mature enough to handle this? We might think we are, but do we know? And this … this is …” he struggled to say the next word, but it had to come out. “… incest! … What does that mean for us? Can we ever be in a relationship? I don’t want …” Dipper voice cracked, and tears sprang unwittingly from his eyes. “I don’t want you to give up something so important … for someone you can’t be with!” Dipper finished with a sob.
Dipper had confessed to Mabel his biggest fear that he had been thinking about since the waterfront. He was scared that he would spoil Mabel’s life, that he would ruin her chances for a normal life and happiness because he selfishly wanted to indulge in something they may regret. He was scared that she would someday view this night as the rest of world would view it: an immoral, perverted act between twin brother and sister.
And because he thought he was a responsible, protective brother, he took it upon himself to make sure that he would, on her behalf, consider these consequences to Mabel. He didn’t assume that she would have considered any of these for herself.
Dipper was incorrect. Mabel had thought of these issues all day. She loved how sweet Dipper was, how he so obviously just wanted to do what best for her, but she had to get through to him. She kissed his eyes, tasting his tears, then backed away so that he could see her face clearly. She still held his face in her hands.
“Dipper … I’m old enough to know that I’m in love with you. I am mature enough to know that making love will change things between us, but because it’s with someone I’m in love with, it’ll only be better! I know that I love you. And I know you! I know you love me too … I … I can't ask for more than that! I don’t care that you’re my brother, except that … except that being my brother makes me care about you even more! I don’t care if we can’t be open about ourselves to the world! I don’t care if we can never be together again! … No one can ever be who you are to me! I will never be sorry for anything we do! You want me to save myself? For someone else? Who could I ever choose before you? … I want you to be my first! I want to be your first! I … I’m sure, Dipper! I’ve never been so sure of anything!” Her voice was starting to break, as she became more desperate to find words to match her emotions.
It was the longest speech Dipper could ever recall Mabel making. His tears continued to roll down his cheeks. He was touched and surprised to hear such confidence and conviction from her. He saw that she had thought this through, more than he had.
Mabel paused, fearing the answer to her next question. “Are you sure you want to do this?”
Dipper also paused, wiping his face with his hand. “I don’t know that I was sure or not,” looking down as he replied, then looked back into Mabel’s eyes. “But I am sure now.”
They both closed their eyes as Mabel drew his face to hers, and they sealed their bargain with a long, gentle, loving kiss.

After they had agreed that they would consummate their relationship, Dipper didn’t feel that the proper way to move forward would be to just climb on and start fucking. At any rate, impromptu debates about the pros and cons of entering into an incestuous relationship can put a damper on one’s sexual readiness. Given the half-mast status of his penis, it wouldn’t have been possible for Dipper to perform at that moment, even if he’d wanted to.
Mabel had also noticed the lack of firmness in the organ that was pressed up against her hip as they held each other. A mischievous twinkle was growing back into her eye after the seriousness of their talk. She motioned down with her head. “Is he okay?” she asked, smiling sincerely.
Dipper smiled back at the assignment of gender to his penis. “Yeah, I guess I wasn’t feeling very sexy for a few minutes, there,” he explained. “I’m sure we can get him going again!” as he started snuggling back up to her body.
She pushed back against his chest. “Oh, no! You’ve been ignoring him, haven’t you?” she said with faux shock and outrage. Dipper was confused, but amused. Mabel pushed harder and rolled him on his back. “I will not stand for this! I will be … his hero!” as she quickly crawled down over his hip. Mabel had decided that if Dipper could just launch a sneak attack of oral sex on her, well, two could play at that game!
Dipper barely had time to register what Mabel was doing as she engulfed his partially-erect penis into her mouth. Mabel would never have believed that she could ever have done this before that night. With no inhibition left, she was willing to do anything at all for her brother. With one hand she held the base of his penis, and with the other she cupped and tickled his testicles. She knew that teeth would probably not be appreciated, so she hid them as best she could and pulled her mouth back, sucking as she slid her lips and tongue over the sensitive skin, then kissed the tip and lowered her mouth back down. By the third time down, she already felt that Dipper was harder and thicker. By the fifth time, it had swelled to the point that she could no longer get her mouth all the way down to the base. Mabel stopped with her mouth full, and glanced up to see Dipper’s expression.
For his part, Dipper had never seen or felt anything that turned him on so much. The sensations of Mabel’s mouth on his penis, combined with the awe of what she was doing for him, aroused him faster than he could fathom. His face must have conveyed this well, because the edges of Mabel’s mouth curled up. Then she slowly backed off, suctioning and caressing with her tongue the entire way, until she pulled all the way off with a wet smack. She kissed and licked it a few more times, as Dipper stroked her hair and gently palmed her cheek, pulling slightly to get her to bring herself up to his face. He could feel how quickly his arousal was building, and he didn’t want to come again, not yet. Keeping up the massaging of his testes and with a sly smile, Mabel kissed her way slowly up his body until he finally had to pull her up by her armpits so that he could grab her head and kiss her on the mouth fiercely.
“You are going to be his hero forever!” Dipper breathed between kisses.
Mabel moaned into his mouth, shifting herself around to lay on her side next to Dipper. She was grinding herself into his right hip, working one leg beneath him and the other on top, while she reached across to his opposite shoulder. She wanted Dipper so badly now. She was about to grab her brother and pull him on top of her.
Dipper had other plans. Mabel may have said that she didn’t worry about it hurting for her on her first time, but he would be damned if he wouldn’t try his best to make sure that didn’t happen. Simple physics said that if Mabel were on top, she would be able to control how deep and how fast her penetration happened. Also, he knew from his own experience with masturbation that he had a better chance of lasting before his orgasm if he was on his back.
So instead of waiting for Mabel to try to pull him over, Dipper stayed on his back where he was and pulled Mabel up onto himself. She pursed her lips into an “ooooh” face, understanding what Dipper wanted.
Straddling his waist with her legs, Mabel allowed Dipper to pull her down to him. She settled her weight down on Dipper’s chest and they shared in a long, deep kiss, holding each other tightly. Coming up for air, Mabel wiped her hair from Dipper’s face and looked down into his eyes. A mixture of nerves and anticipation filled her. “You ready?” she asked him quietly.
Dipper was trying to be cooler than he felt, but his brain was not cooperating. All he could come up with was a small “Yeah!”
Mabel sat up, rocking herself on his thighs below his hard penis. With her left hand, she reached to stroke herself, verifying that she was wet, and gave herself a quick pinch on her clitoris. With her right hand, she stroked Dipper’s penis up and down slowly, mentally preparing herself for it to be inside her in a few moments. His hands stroked her thighs, hips, and waist, not wanting to rush her. She smiled lovingly. Because Dipper had insisted on her being on top, it was a sign of how much he trusted her, as it put her in control of their coupling.
She moved forward and raised her body up, and rubbed Dipper’s penis against the front of her slit, down over her clitoris and back up again. New shivers of pleasure ran through both of them, as Mabel lightly masturbated on Dipper’s tip.
Finally, she was ready. Mabel held Dipper’s penis to the opening of her vagina, and they both watched and felt the head slide snugly inside. They both inhaled sharply, then together they looked from their merging crotches to each other’s faces. And together, they whispered, “I love you!” and then smiled. Twins!
The smile stayed on Mabel’s face as she closed her eyes and craned her neck up, resting her hands on Dipper’s shoulders. Then, slowly, she let down her weight, forcing Dipper’s penis into herself. She was aware of a whole new class of pleasure as he slid past nerve endings that had never been touched before. There was a stretching sensation, but nothing that she would ever describe as pain.
Dipper was watching his penis disappear into his sister. He could feel the wonderful, moist warmth surrounding it. She was tight, and his foreskin was being pulled down over the sensitive head as it went in, which only added to the stimulation. He couldn’t stop himself from slowly raising his hips as Mabel bore down.
Finally, their pubic bones met, their virginities gone. Mabel’s breathing was shallow and quick, her body quivering with thrilling new feelings. She was now pushing down hard, as Dipper was pushing up just as hard while pulling on her hips, making tiny thrusts into her, trying to get inside even deeper.
Dipper felt a boiling sensation in his testicles, and was aware that he could come any second, so he relaxed his pelvis. Mabel also stopped pushing and bent down on her brother with wide-eyed wonder. “Oh my God!” she breathed. “Oh … my … God!”
“You’re incredible!” Dipper panted back, unconsciously thrusting his hips again, sending another thrill into his sister. “Are you okay?”
“Oh God yes!” she gasped back. “You feel so good! I love you so much!” She reached down and gave Dipper a quick, hard kiss on the mouth.
Dipper caressed Mabel’s face. “I love you too!” he replied with an excited smile. Then he swiftly slid his other hand from Mabel’s hip to underneath her breast, raised his head from the bed, and tried to inhale as much breast as he could while rolling her nipple around on his tongue.
Mabel cried out, almost softly, as Dipper’s mouth and penis combined to send even more electricity through her senses. Automatically, her hips began moving, as she and Dipper began a gentle rhythm together.
Dipper experimented with pleasuring Mabel’s breasts. He rolled her nipple with his tongue, kneaded with his hands, kissed everywhere, and gently sucked. He tried to duplicate Mabel’s sucking technique on his penis, keeping his teeth under his lips, but as he pulled off to switch to the other breast he slipped and the nipple grazed his teeth. Mabel gasped loudly and tensed.
“I’m sorry,” Dipper apologized. “I didn’t …”
“No!” Mabel looked back at him. “Do that again!” Dipper happily spent the next few minutes adding gentle bites and chewing on nipples to the list of ways to add pleasure to their sex play.
The twins were both trying to not lose control, wordlessly agreeing to try to make this moment last as long as they could. But the speed of the movement of their hips was accelerating, and their bodies were coated in a film of sweat from the exertion of their efforts.
When Dipper’s teeth made an especially sweet impact on her left nipple, Mabel could not hold back any longer. She groaned loudly, sat straight up to push Dipper into her as far as possible, and started grinding with abandon. She could feel her orgasm was just below the surface, and she wanted Dipper to come with her.
Dipper could not imagine a sight more erotic than what he was seeing. His beautiful sister, face flush with passion, was pounding and gyrating her body onto him. He could see his penis appear, then disappear back inside her as she pushed down to meet his upward thrusts. He could see her gorgeous breasts bouncing perfectly to the rhythm of their movements.
He was getting close to his climax again, and he knew he couldn’t stop it this time. By now Dipper knew Mabel’s noises and knew that she wasn’t close enough, that at this pace he would come before she had an orgasm. Through his frenzy, he saw an opportunity to help her. While increasing the pace of his own pelvis, he let go of her hips and reached down with his thumb to rub Mabel’s clitoris while pinching hard on one of her nipples.
Mabel convulsed and shuddered. She let loose a guttural, strangled scream as Dipper attacked her three most erogenous zones at the same time.
Dipper couldn’t hold on, he was over the brink. The pressure built to an agonizing crescendo, then burst in the most intense release of pleasure in his life. He practically shouted through his clenched teeth as he felt his semen fill his sister.
Her orgasm was just hitting when Mabel felt the first pulse of her brother’s penis and sensed his ejaculation firing on her cervix. Overwhelmed, she flung herself forward onto Dipper as it felt like her insides had exploded in joy. She buried her face in his neck, screaming and crying. Her body was quivering, every muscle dedicated to trying to squeeze Dipper and herself together into one body, one soul. Dipper was squeezing back desperately, sharing in the intensity of their love.

They finally began to come down from their passionate high. Dipper’s lungs realized they hadn’t inhaled in some time, and he took breath after breath to get oxygen to his brain. Mabel was also panting heavily, as she relaxed her grip and just lay exhausted on Dipper’s heaving chest.
After they had mostly recovered, Mabel raised her head, and Dipper turned his to her.
Dipper gazed at his sister in wonder. She was everything to him! Partner in mischief. Mystery Twin. Best friend. Soul mate. Love of his life.
Mabel stared smiling tiredly at her brother. She loved every bit of him. She didn’t think she could be happier, and she adored making him happy, too. Best brother ever!
“I love you so much!” they said together. They laughed softly, resting their foreheads together.
Mabel thought she was getting heavy on Dipper, so she slid off and they curled up together on their sides, stroking each other slowly and kissing deeply and lovingly. She tried to stifle a yawn, but when Dipper also yawned, hers emerged as well.
“You tired, too?” she asked, stroking hair from his face.
“Yeah. It’s been a long day,” Dipper replied quietly. “We need to clean up before we go to sleep.”
Mabel flopped over and spooned in to Dipper, pulling his arm around her. “Just a few more minutes of snuggling. Everyone needs snuggle time on their birthday. It’s a new birthday rule I’ve just decided on.” Mabel’s voice was a dreamy sing-song.
“Technically, it’s not our birthday anymore, goofball,” Dipper said, nuzzling the back of Mabel’s neck, intertwining his legs into hers, and letting his hands fall easily to her breasts. “It’s Sunday,” he said drowsily.
“Shut up, nerd,” replied Mabel smiling, her eyes closed.
- 7
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- 9
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Fistbump (a Pinecest story)