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Biological Imperative	By : GeorgeGlass Category: +G through L > Lilo and Stitch Views: 43393 -:- Recommendations : 4 -:- Currently Reading : 2
Disclaimer: I do not own Lilo & Stitch or its characters. I made no money from writing this story.

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Biological Imperative
by George Glass
Summary: A set of dormant genes awakens in Stitch, and Lilo and Nani’s lives will never be the same.
Note: Unlike all of my other fanfics up to this point, this fic is not based in canon. Rather, it is inspired by various pieces of Lilo & Stitch rule 34 artwork that I’ve seen over the years. This story is not intended to accurately reflect any aspect of the movies, TV series, etc.
Second note: This is all fantasy. I don’t endorse anything that happens in this story.
Third and final note, I swear: If you are kind enough to review this story, I’ll respond to your review here: http://www2.adult-fanfiction.org/forum/topic/69125-review-responses-for-biological-imperative-lilo-stitch/
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It was bedtime, and Lilo had just brushed her teeth and climbed into her bed. As usual, Stitch was in the bed with her—an arrangement the two of them had preferred since the beginning. Lilo found Stitch’s presence more comforting than that of any stuffed animal, and Stitch liked being near Lilo.
“G’night, Stitch,” she said, turning out the light.
“Night-night, Lilo,” Stitch replied in his raspy voice.
Stitch didn’t seem very sleepy, though. Lilo felt him toss and turn a bit on the bed, so she closed her eyes waited for him to settle down. He didn’t, though, and after a few minutes of restlessness, he spoke.
“Lilo awake?”
“Yeah,” Lilo answered.
“Stitch need Lilo’s help.”
Lilo turned the bedside light back on and blinked in the brightness. “With what?”
Stitch pushed the covers down, and Lilo was surprised by what she saw: At the junction of Stitch’s thighs were two thick, black cylinders of flesh. Each one was about the size of Lilo’s forearm and had a rounded head with a little hole at the tip.
“Need help with these,” Stitch said. “Need to make them not-full. Full is hurting.”
“Oh, no!” Lilo exclaimed. “How can I help?”
Stitch stood up on the bed in front of Lilo. Then he took her hands in his.
“Hold bottom one,” Stitch said. “Like this.”
He put Lilo’s hands on his lower member, wrapping them around it as much as the organ’s thickness would allow.
“Now, move hands like this,” he said.
He pushed Lilo’s hands forward and then pulled them back, so that the thick skin on the outside of his shaft covered and then uncovered the underside of the head. He did this twice more, then released Lilo’s hands. She continued the motion on her own.
“Yes, that is helping,” Stitch said, his voice even raspier than usual.
“Really?” Lilo said, looking at Stitch’s shaft, which was thick and heavy in her hands. “‘Cause it looks even fuller than before.”
“We can fix,” Stitch replied.
He put two of his hands on the base of his upper cock. Then, with his other two arms, he pulled Lilo up into a kneeling position, such that the tip of his upper member was inches from her lips.
“Put top one in mouth,” Stitch said.
“In- In my mouth?” Lilo replied, looking wide-eyed at Stitch’s upper member.
“Uh, Lilo don’t have second pair of hands. Need use mouth instead.”
Lilo eyed Stitch’s turgid member dubiously. She wasn’t sure if she could get something of that girth into her mouth.
“Please, Lilo,” Stitch insisted. “Will make Stitch stop hurting.”
She looked up at Stitch, her eyes big and watery with anxiety. But she had to help him if she could. He was her best friend.
“O- Okay,” she said, her voice quavering.
Stitch put the head of his upper cock to Lilo’s lips. There was something wet and slippery leaking from the little hole at the end, which felt weird on Lilo’s lips but which didn’t seem to taste like anything.
“Lilo open wide,” Stitch rasped.
She opened her mouth as wide as she could, and Stitch pushed the thick, black head of his cock inside. Lilo tried to relax her mouth a little once it was in, because it was a strain to open that wide, but she found that she could barely do so; Stitch’s member was so thick that her mouth was still open almost as far as it could go.
“Yessss,” Stitch breathed. “Very good. Don’t forget hands.”
Lilo realized that she had stopped stroking Stitch’s lower member. She started moving her hands up and down it again, even though she could no longer see what she was doing.
“Nnnn, yes, yes,” Stitch said. “Lilo keep going.”
Stitch moved his hips forward a little, pushing another inch of his upper cock into Lilo’s mouth. Lilo was afraid he would keep going and choke her, but then he pulled back again. He continued pushing his thick member in and out of Lilo’s mouth that way, making her lips move across the underside of his cockhead in much the way that her hands were moving on his other cock.
Wanting to help, Lilo kept at it, but at the same time, she hoped Stitch would be finished soon. Her jaw was already getting sore from being open so wide, and her hands and arms were starting to get tired from rubbing his lower member.
Maybe Stitch knew this, because now he put two of his hands back on top of Lilo’s and helped her massage his lower cock. Stitch was much stronger than she was, so once he began helping, all Lilo had to do was keep her hands wrapped around Stitch’s member while he did the rest.
He was making her rub him faster than before. At the same time, he moved his other two hands from her shoulders to her head, and he started pushing the head of his upper cock more quickly in and out of Lilo’s mouth. Now, his thrusts penetrated a bit deeper, causing Lilo to gag a little whenever it went in too far.
“Nnnnnnh,” she said, trying to tell Stitch to stop or at least slow down but unable to form words with Stitch’s thick penis in her mouth. “Nnnnnnh!”
Stitch could barely hear Lilo’s protests. Driven by powerful urges—ones taken from nature but magnified tenfold in his creator’s laboratory—Stitch panted as he thrust his upper cock faster and harder into the little girl’s mouth while making her small, soft hands rub his lower one ever more vigorously.
“Good, Lilo,” he gasped, barely aware of his own words. “Almost finished…almost…”
His thrusts into Lilo’s mouth grew even faster and deeper, making her gag more forcefully now as his cockhead hit the back of her throat again and again. The girl tried to move away, to expel the thick invader from her mouth, but Stitch’s grip on her head was like iron.
“Yessssss,” Stitch hissed, now fucking Lilo’s mouth rapidly and using Lilo’s hands to rub his lower cock at blinding speed. “Yesss, yes, yes!”
As orgasm struck and Stitch began to shooting thick white seed from both of his cocks, he felt an overwhelming urge to shove his upper member farther into Lilo’s mouth, to make her swallow as much of his load as possible. Holding her head immobile with two of his inhumanly strong hands, he thrust his cock all the way to the back of Lilo’s throat.
“Nnnnggglllgh!” Lilo screamed around his dick.
“Lilo swallow!” Stitch gasped. “Swallow all!”
“Ggggggllb! GGGGLLLLLLLB!” Lilo gurgled, her mouth now so full of cock and thick semen that she could not breathe, the head so far in that much of Stitch’s cum was shooting right into her throat and down into her belly. His lower cock splattered her chest thickly with more of his seed, so much that it soaked her nightgown from her neck to her navel, and Lilo could feel the hot liquid spunk on her bare skin beneath.
When Stitch finished, he felt the greatest sense of relief he had ever experienced. Nonetheless, while his two upper hands released their grip on Lilo’s head, his lower ones took hold of her chest, driven by instinct to rub as much cum as possible into the girl’s skin. When his thumbs found the coughing, gagging, gasping Lilo’s small nipples through the soaking-wet fabric, he rubbed harder.
The girl alternately coughed and gasped for air for almost a minute. Then she looked up at Stitch, her round face streaked with tears. Stitch felt a pang of guilt and let go of Lilo.
“Please,” Lilo gasped. “Don’t ever make me do that again.”
Stitch ran a blue hand through the girl’s now messy hair.
“Stitch sorry,” he said. “But Stitch fine now. Lilo help Stitch a lot. Maybe even save Stitch’s life.”
Lilo blinked. “R- Really?”
“Yes.”
Stitch didn’t actually know if this was true. But at the very least, Lilo had kept Stitch from losing his mind by satisfying the sudden, irresistible need that had arisen inside him. He helped Lilo out of bed.
“Stitch help Lilo clean up now. Then we go to sleep.”
“Okay,” the girl said weakly, and let Stitch walk her to the bathroom.
Inside Lilo’s stomach, millions of alien cells were on the move. These were sperm cells, much like those produced by any Earth animal, but they had been engineered to perform another function, too.
Impervious to Lilo’s stomach acids, the sperm migrated through the membranes of her digestive system and into her bloodstream, where they began releasing a flood of specially designed, bio-adaptive hormones into Lilo’s system. At the same time, the sperm cells on her skin penetrated into her dermis, infusing it with the same hormones.
Lilo wasn’t aware of any of this. Nor was Stitch, even.
All Stitch knew was that despite what he had told Lilo, he was almost certainly going to need to do this again. This, and maybe more.
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Biological Imperative