Lust from Space!

"Sara," Lucy said. "I feel funny."

"Funny how?" Sara was worried that maybe the effects of the plants were too strong for the younger, smaller girl. "Woozy?"

"No," Lucy said, looking Sara in the eyes. She was clearly not drugged. "Just funny. Excited a little."

Sara needed to get back down into the underground forest. This she knew. "It's OK," she said to her sister. "Wanna explore downstairs?"

"I feel like I need to," Lucy said. "You feel the same way, don't you?"

"Yeah."

Sara went first again, and when she reached the bottom of the ladder, she felt a cooling sense of relief. She looked around at the glowing plants, marveling once more at their beauty. When Lucy reached her, they both stood for a while as Sara let the girl take in the view.

"Oh my god!" Lucy whispered, as if she was in a library. "How did you find out about this place?"

"It was when I was in the time bubble the first time," Sara said. "I was running out, and I saw the blue light from one of the holes in the dome."

"This place is amazing!" Lucy said, approaching a bush covered in chains of glowing orange spheres, her hand reaching out to it.

"Hey!" Sara called to her sharply. Lucy stopped on a dime and looked back. "Don't touch anything. We don't know what all these things are."

Lucy's hand shot back to her side. Bad memories of poison ivy the previous summer danced in her head. Just the thought of it almost made the younger girl itch. "Right," she said.

For a while, Sara and Lucy walked through the corridors of what Sara was coming to understand as a system of halls and rooms, almost like an old library. Interesting, she thought, that Lucy had naturally assumed they were supposed to be quiet. And then she remembered the previous night.

As the vine in buried in her tight young pussy had rubbed against her clit on every thrust, she had screamed like a banshee as she came. Perhaps, she thought, the rules changed when the inhabitants fucked young humans. The memory made her head spin, and when she finally shook it off, she noticed that she could feel a single trickle of moisture running down the inside of her leg. She had put on slightly baggier shorts than the night before, and had skipped wearing panties, so there was nothing to stop the wetness. Fortunately, the dim light and her sister's fixation on the multitude of alien plants around them let the moisture go unnoticed.

The path they took was, in Sara's estimation, in the exact opposite direction than the way she'd walked before, but she got the sense again that they were being guided. Even Lucy felt it. "I feel like we're being watched," she said.

"Yeah," Sara said, taking her sister by the hand and leading her further into the tunnels. "I know what you mean."

"So are we?" Lucy asked. "You've been here before."

"Not exactly," Sara said, feeling a sense of deja vu.

"What does that mean?"

Sara stopped short and Lucy nearly bumped into her in the dim light. This was definitely the same doorway she had come to last night. Butterflies filled her stomach, but in the back of her mind she worried how her sister might react if what happened to her last night happened again. She felt her pussy become sopping wet thinking about it, but it was one thing to show her sister how she fingered herself, as she was sure Lucy had expected, and another thing entirely to have the younger girl watch as a tree fucked her silly. Still, she put one foot in front of the other and passed through the doorway, sister in tow.

"This is where you came last night," Lucy said.

"Under the tree, yeah," Sara said, bending the truth for just a few minutes more.

"How'd you get to the there?" The girls stood just inside the large chamber, vine-laced tree dimly glowing veins of gold before them in the center. Surrounding the tree, however, the ruby-glowing thorny bushes grew thick and wide, blocking the path that once led directly there.

"It wasn't like this before," Sara said. "Wait here." Sara dropped Lucy's hand and stepped forward to examine the bushes, trying to find a path through. When she approached, the bushes parted.

"Whoa!" Lucy cried. "That's incredible!"

"That's not the half of it," Sara said, her mind trying to wrap itself around how all this was working. "Come on." Sara continued forward, and the bushed parted in front of her, but as Lucy approached, they closed, blocking her path.

"Hey!" Lucy called. "What the hell!"

Sara turned and started back toward her sister. The bushes allowed her to pass. Halfway back, some idea that had been churning over and over finally clicked. The ruby flowers, the thorns. Sara looked at the spot where the thorn had snagged her wrist. When she reached the edge of the thicket where Lucy waited, the bushes ceased to part. "Give me your hand," Sara said, extending hers to the outside of the thicket.

Lucy looked as if she was going to say something, but then simply reached out and took the offered hand. "Nothing's happening," she said.

"Not yet," Sara said, gripping her sister's hand hard. A wild look of fear flashed onto Lucy's face as she realized what was about to happen, but she didn't have time for words. Sara yanked and the smaller blonde girl came crashing through the thorny branches, collapsing in the dirt at her sister's feet.

"Aaah! Ow!" Lucy yelled, tending to her scratched arm and legs. "Why'd you do that?"

"Look," Sara said, gesturing toward the tree. A clear path lay between the girls and the tree. Sara showed her the nearly healed scratch on her wrist from the night before. "I think they need a sample of blood. Like a key or something."

Lucy still seemed angry. "They?"

Sara stroked one of the glowing ruby flowers. Lucy's anger immediately evaporated as she watched the delicate luminescent petals ripple under her sister's touch. There was something about it that made her feel a little hot and funny, like she did when she needed to play with herself. As Lucy reached out to stroke the petals, Sara dug into her daypack and pulled out a small piece of cloth and wiped the tiny beads blood from her sister's scratches. "Sorry," Sara said. "I'm still figuring this place out."

Sara helped her sister to her feet, and they continued down the cleared path, Lucy running her hands over glowing ruby petals as they went. Sara noticed that her sister seemed to shiver each time her fingers stroked another flower. When they reached the tree, Lucy noticed the dampness of the vines. Before Sara could say anything, Lucy reached up and touched the first one she could reach. She would have said something, but Sara wanted to see what kind of reaction her sister would have. As the younger girl brought her now damp fingers to her nose, her eyes went wide. "It smells like me," she said, warily. "I mean, down there. My-"

"Pussy?" Sara finished. She dropped her pack in the dirt and started unbuttoning her shirt.

"Sara, what're you doing!?" Lucy asked, flustered.

"I thought you wanted to know how I did what I did," Sara said, pulling off her shirt and unhooking her bra. She found that the lust she'd known the night before had been a pale shadow of the passion she was feeling now. Nothing would stop her from being satisfied, not even the prying eyes of her younger sister.

"I did," Lucy said. "I mean I do."

Sara turned to stuff her shirt and bra into her pack, and while she was at it she pulled off her boots and let her loose shorts fall over her hips, exposing her bare ass and pussy to the cool air. She knew that any moment, she would feel the grasp of roots and vines. She turned back to her young sister to explain that she was about to witness something really strange, and not to worry, but when she did, Lucy was removing the last of her socks. "What're you doing?!" Sara gasped.

"I'm feeling really hot, and I need to play with myself," Lucy said. Honestly, the wooziness she'd been feeling was rapidly turning into full-blown desire. "If you're going to show me, I can just copy you, right?"

Sara stared at her naked little sister, her small firm breasts and her smooth skin, and felt a dozen different thoughts screaming at her. Before she could say or do anything more, two soft roots popped from the dirt and wound themselves around Lucy's ankles. Panic struck, and the girl bent down to try and free herself. "Sara!" the younger sister cried. "Help me!"

Sara found herself frozen in place, trapped between the desire to free her sister from what was sure to be a rough deflowering and the lust that made her want to watch. She watched the blonde girl's fingers pry at the roots to no avail until two more roots quickly took the girl's wrists. Off balance, Lucy fell forward on to her hands and knees and the roots pinned her there. "S-sara," her little sister pleaded. "What's going on?"

Sara couldn't rightly, say. The vines in the tree made no move toward the girl, who simply remained pinned. "I don't know," Sara said. "This is different from last night." But as helpful as she wanted to be, the older sister's lust could not be overcome. She went and knelt by her sister, whose eyes, wide with fear and uncertainty, reflected the myriad glowing colors in the room.

"Tell you what," Sara said, running her fingers sensually through her sister's hair. "While you're stuck there, I'll show you what I did last night, OK?"

"OK." Lucy swallowed some of the terror back, and desire quickly filled its place. "But Sara?"

"Yeah, sweetie?"

"Could you run your hands through my hair again? It felt kinda nice."

Sara felt boundaries breaking down in her mind, and he strangest part about it was that despite all of the alien influence on her lust, she knew that she was the only one breaking down the boundaries. "Of course," she said, and, kneeling in front of her sister, ran her fingers deep into the girl's hair, feeling her scalp prickle at the touch.

"Mmmm," Lucy sighed, tilting her head back. "Again?"

When Lucy spoke, Sara felt her warm breath on her breasts, and it made her dizzy. Sara ran her fingers through the girl's hair again, and when she was done, she dragged her fingertips back over her sister's shoulders, flipped her hands over, and continued down the girl's chest until her hands gently cupped the two small breasts that hung there. "Uh," Lucy said, clearly starting to feel the lust and pleasure of this place, but not as far gone as her sister. "Uh, Sara. You shouldn't do that. It's wrong."

"You don't sound convinced," Sara said with a mischievous smile. She lightly pinched her sister's nipples, causing the younger girl to let out a breath.

"Oh!" was all Lucy could say.

Sara stood up suddenly grinning. "Something to think about," she said, taking a few steps back. When she did, two roots wound around her ankles. Lucy gasped as a vine drooped from the tree, looping around her big sister's body. The vine began to tighten, sliding smoothly up Sara's body and catching under her arms. It pulled higher, raising her arms, and once the loop was past her head, it tightened, around her wrists, binding her hands above her head. The two roots then moved in the dirt, spreading Sara's legs. Lucy could now see clearly how wet her sister had become.

Sara felt the cool air against her exposed pussy and shivered with pleasure. She saw her sister watching her and for a moment became a little self-conscious. As the vine binding her hands pulled her arms taught above her head, she saw another vine drop loosely from the tree above Lucy. The younger girl started when its blunt tip touched the middle of her back, and Sara wondered what would come next.

As the tree had done to Sara the previous night, the vine on Lucy's back sprouted a hundred smaller glowing versions of itself that began to spread over the girl's body. "Oh, god!" Lucy whimpered, squirming. Bound as she was on her hands and knees, she couldn't see what was going on. "What's happening?"

"Don't worry," Sara cooed, watching the tiny sprouts wind their way around her sister's developing curves. She noticed that the little tendrils were heading for different spots on the bound blonde girl than they had on her. The first group went up the back of Lucy's neck and into her hair. "Eek!" Lucy blurted in surprise when she felt them there, but turned it into a pleasured "Ahh..." as they apparently worked a kind of magic that Sara's fingers could not. A second group of tendrils wound down her arms nestling in the crook of her elbows and on the soft inside of her wrists. Sara saw the girl's arms twitch as the teasing plants caused her muscles to nearly fail her. "Oh!" the girl moaned.

Sara thought that that place on Lucy must be like the spots behind her own ears. As if the plants were reading her thoughts, she felt a sprouting mass across her back. Wow, she thought. She had been so lost watching her sister get teased by these little tendrils that she hadn't even noticed the vines around her own body.

Lucy's neck had relaxed so much from the wonderful feelings she was getting on her neck and scalp that her head hung loosely between her shoulders. The tendrils that had been massaging her there suddenly tightened, pulling her head up by her hair. "Ah!" Lucy cried. But she paid the discomfort no mind when she saw the miniature vines creep over her older sister. So that's what that feeling was, she thought. Lucy watched as the tendrils wormed their way behind Sara's ears, and saw the older girl heave an ecstatic breath. More wound around Sara's stomach, and when they reached her breasts, they wound gently around her nipples. Lucy saw her sister's knees buckle, but the vines binding her hands held her up. The sight of her sister in the throes of so much pleasure started to make the younger girl jealous, but she wouldn't have to wait long.

As the tendrils continued to tease and stimulate her, Sara saw that Lucy was being forced to watch. And as Sara looked her sister lustily in the eyes, the tendrils continued their exploration of the younger's body, climbing down to her belly and to her little pert breasts, where they wound much more tightly than they had on Sara. The girl squealed as the tendrils squeezed her sensitive nipples. "Aah! Aaaah!" the girl cried. Sara worried through the waves of pleasure that her sister was in pain, but a dopey smile crept across the younger girl's face. As the tendrils crawled over Lucy's butt and down the backs of her thighs, Sara saw the girl's eyes roll back in her head. Once all of the tiny vines had found their spots and settled into teasing the girl, Lucy's eyes finally readjusted, focusing on Sara.

A thick vine from the tree dropped down below Sara's knees, wrapping itself around her leg and winding its way up her thigh. Lucy watched this and panted as her own tendrils teased her breasts and thighs. When the vine reached Sara's wet pussy, it paused. "Come on," she pleaded, her head tilted back in erotic frustration. Lucy took in a sharp breath as she watched the vine press against the entrance to her sister's pussy. As it popped in, Lucy watched inch after girthy inch of it disappear into the older girl.

"Oh, god," both of them said at once. In Sara's case, it was from the pleasure of feeling the vine fill her tight wet pussy again. For Lucy, it was the realization that this was what had happened last night. The thought of it made her incredibly horny, a sensation she had just been getting used to, but it also made her realize that her sister was no longer a virgin and that, by the end of the night, she may not be, either. That thought, too, brought on a mix of emotions, both erotic and troubling, but they were but a drop in the ocean of pleasure wasting over her.

Sara felt the vine begin to pump in and out of her, rubbing tightly against her clit on every thrust. Again, her knees buckled, but she remained upright, hanging for a moment from her bound hands. "Oh, fuck!" Sara cried as the vine sped up. "Oh, fuck me! Fuck meeee!" She could feel the thick vine filling and leaving her burning pussy again and again, and her words became moans.

Lucy saw the thick vine stretching her sister's bare snatch, pumping in and out furiously, and combined with the teasing and stimulation from the tendrils on her own body, she felt ready to explode in lust and jealousy. "Oh, shit, I'm coming!" Sara squealed suddenly. "Coming, coming! Oh fuck!" Lucy watched her sister's body convulse in ecstasy. The pumping of the vine slowed in time with Sara's convulsions. When it finally popped out of her, Sara hung on the vine that bound her hands, twitching.

When the roots binding Sara's feet released her, and the vine she hung from lowered her to her knees and unbound her wrists, Lucy wondered if she was still bound because the same thing was about to happen to her. Anticipating a ravaging, the girl tensed up.

Sara, panting on her hands and knees, raised her head and noticed that her little sister was still bound. The tendril seemed to be working their best, but the girl was tense. Sara crawled over to her, noticing with amusement that with the glowing green tendrils wound into her blonde hair, she looked kind of like Medusa. A very, horny, flushed Medusa. "Why hasn't it let me go?" Lucy asked, nervousness just barely penetrating her heavy breathing.

"I don't know," Sara said. She traced a finger down the length of a tendril on the girl's shoulder and felt an almost electric sensation in her fingertip. Lucy shuddered. "Like that?"

"God, yes!" said Lucy, surprised. Somehow the connection amplified the pleasure she got not just from the one tendril, but from all of them. "Do it again!"

This time, Sara traced the tendril down from her shoulder and to the girl's breast, following the spiral all the way to the nipple. Lucy moaned wordlessly, arching her back up and then down as the sensation sent bolts of pleasure arcing through her body. "Ah!" the girl cried. "Ha!" Sara took her other hand and placed it on her sister's other breast, causing the girl to buck. No longer able to make sounds, Lucy was reduced to breathy gasps as her older sister helped the plant pleasure her. Her head still held back, she couldn't see what was going on under her, but did have an excellent view of her sister's larger pert breasts. She felt her pussy become sopping wet, and an irresistible itch began to form in her belly.

As Sara played with her sister's breasts, she suddenly felt a warm sensation on her breast. She looked down and saw Lucy's tongue reach out and flick her nipple. Jeez, she thought, her sister must be completely horny. Sara leaned forward, pressing her breast to Lucy's mouth, causing the both girls to moan. Lucy's tongue ran circles around the older girl's nipple, and Sara felt sparks, gripping her sister's firm breasts a little harder.

The lust cascaded into a fever pitch when Sara noticed a vine dangle down behind her sister. It wasn't as thick as the one that had just fucked Sara, but it was plenty big enough, the older girl saw. Lucy made a hesitant sound when two more root popped from the ground, grasped her knees, and spread her legs apart. When the vine wound itself around Lucy's waist, the she tried to shift and look back, but Sara helped the tendrils keep the girl's head still and shoved her other breast into her open mouth. The vine tightened and Lucy's pussy lips parted as she straddled it. "Mmmf!" she groaned into Sara's breast, when she felt the slickness of it against her little clit. Lucy shifted, trying to free herself of the vine between her legs, but the more she did, the more the "Mmmf!" became "Mmmm!"

Lucy had begun to grind against the vine, and her tongue resumed its circles around her big sister's nipple. The sensation was incredible, much better than her fingers had been. She felt a rising tension in her body and ground against the vine harder. Lucy had never been able to make herself come before, but now she was about to know what it felt like. Just before the girl was about to come, the vine instantly went slack. Lucy whimpered.