An Avenger's Guardian

"Open wide Terran..."

Feeling the tip of the dildo brush her bottom lip, Natasha opened her mouth to receive Gamora's cock. Nebula laughed, a short, cruel sound-echoing overhead as the dildo slid between her teeth. It was a tight fit; Natasha's jaw straining as it stretched to accommodate the artificial shaft's enormous girth, feeling the odd tasting metal scrape against her vulnerable throat as she descended.

Pressing her tongue down against the floor of her mouth, Natasha waited as, inch by inch, Gamora's phallus disappeared between her lips. Heart pounding in her chest, Natasha gagged at the influx of oil that poured down her gullet as the blue alien thrusted her head forward, filling her mouth completely.

Natasha swallowed repeatedly; gagging as the cock brushed past the back of her throat. Holding her, Nebula guided her head with strong fingers. Pushing her deeper with no restraint, soon the base of the subjugation tool glided deeper still, pressing against the pulsating muscles of Natasha's strainign throat. Concentrating on suppressing her gag reflex, Natasha struggled in place, her gullet expanding to make room for the heavy phallus.

Gamora groaned, ignoring her sister's smug glare as thousands of tiny sensors lit up across the surface of her new appendage, transmitting every tactile sensation right up into her core; the heat of the redhead's mouth, the wetness of her saliva, the hard edges of her teeth against the unforgiving shaft. It was a tight fit; the girl's tongue working against the underside sublimely. Her occasional helpless, wordless moans sent vibrations up the heavy cock, only stimulating the green woman further still.

Remembering her training, Natasha went limp, relaxing her neck and allowing her mistresses full control of her body. This was crucial, staying calm was ultimately far less painful than resisting as her face was pummeled by her alien captors. Thankfully the pool presented easier circumstances, lubricating every motion of the long metal phallus against the redhead's distended throat.

Nebula set a generous pace, using her tight grip to bob Natasha's mouth onto her sister's waiting cock. Ignoring the human as she struggled to stay buoyant, the blue woman concentrated on Gamora's enraptured expression, sending the redhead back and forth; using the sensation of a hot vulnerable mouth to overcome the assassin's usual control.

Realising she was giving in to Nebula's twisted pleasures, Gamora struggled to care as the blue woman pressed her lips against her own. Swept up in this aggressive make-out session, for a moment the two sisters kissed each other hungrily, their repressed desire rising to the surface as they pressed together.

Pulling away, Gamora gasped angrily, dark eyes narrowing:

"How dare you kiss me!"

Grabbing Nebula's head, she pulled her obnoxious sister back in, sliding her own tongue into the warrior's waiting mouth. One upping her sibling proudly Gamora suddenly remembered the silent promise she'd made to the woman beneath her when they had initially kissed, why she had started this in the first place.

With a final, shuddering breath; heat, lust and adrenaline firing through her body, Gamora wound down her assault on Nebula's mouth; savouring the dual sensation of those cruel lips withthose wrapped around her cock's life-like surface as she finally withdrew.

Bringing Natasha hacking and coughing to the surface, the green woman tried to reassure her. Just as Nebula tugged the redhead away:

"Oh, I am going to fuck the life from you Terran," Nebula growled ravenously, outraged by her sister's sudden rejection.

"She's mine!" Gamora hissed, eyes wide as she tore the weakened human from Nebula's cruel grip:

"Uhhh!" Natasha whimpered through a raw throat, screwing her eyes shut and groaning as she was once again pulled between the warring sisters.

"If I didn't no better sister mine, I'd say you were protecting it!" Nebula griped, gripping the redhead's arm.

Good thing you know better!" Gamora snapped back aggressively, tugging Natasha into her arms.

For a moment nobody breathed, the sisters holding each other back with will alone, Natasha caught haplessly in the middle. Finally Nebula withdrew, bowing her head ever so slightly; much to Gamora's relief. Now she had to reward that admission:

Thrusting Natasha forward, the redhead fell face first back into the pool, Gamora gripping her hips. The invitation was clear, Nebula swimming forward and taking the woman's head in her hands, a devious grin on her lips.

Gripping Natasha's waist, Gamora straightening out the redhead's sagging posture. Feeling a tug as the woman now took Nebula's dildo into her mouth, she was surprised when the redhead willingly spread her legs, inviting Gamora's cock to be pressed against her glistening, dewy folds; For all her naivety, this human was more than willing to play the sisters' depraved game, practically encouraging her and Nebula:

"Never say I don't share" Gamora stated plainly, running a hand up Natasha's back as she met Nebula's eye once more.

Emitting a short, joyless laugh, Nebula buried the length of her entire cock in Natasha's waiting mouth. When she spoke, her voice was dripping with that odd combination of sex and violence the blue woman craved:

"Fair enough. But is this real strength sister mine? Or do you simply want to fuck Terrans?"

Standing back a moment, Gamora had to admit she enjoyed the sight of this beautiful redhead floating before her; legs spread wide open, pussy lips already on full display. But this was the role she had to play; any weakness would allow Nebula to take control. And neither Nebula nor Natasha wanted that.

Mounting the human, Gamora pushed her own strap-on against the woman's entrance. Natasha whimpered around Nebula's steely cock, the head alone sending chills up through her nethers and her flexing abdomen. Giving Natasha a few seconds to adjust, Gamora then pushed forwards in a slow but steady thrust, the assassin not stopping until the entire length of her cock was buried inside the human's pussy.

Natasha groaned around the huge shaft in her mouth, thrown forward by the sudden, inevitable penetration. Clinging onto the first thing she could reach, Natasha dropped her arms around Nebula's sumptuous behind while she struggled to adjust, her fingers digging into taught flesh, writhing on the huge cocks that filled her at both ends.

Nebula watched, morbidly enthralled by the human's erotically powerless display, her image blurred by the shimmering oil:

Sliding back and forth on the two cocks, Natasha's own feelings constantly shifted between pleasure to pain to shock, hard moans, groans and cries of joy strangled by the phallus that filled her perfect mouth.

Gamora was impressed by the girl's fortitude, still somehow staying upright despite the uncomfortable stretching of her mouth and pussy. But that was the power of the pool; lubricating their every move. Slicing her hips left and right, the alien tested the woman's body. Swaying in time, Natasha somehow managed to pleasure both of her captors.

Wanting to be caring, Gamora knew she could hold nothing back, or face her father's wrath. Instead she luxuriated, just enough to slow her penetrations down with seeming like she was being soft. But still... there was something about subjugating another beautiful woman, another assassin, about proving her superiority that made the brunette feel so invigorated: In all her time fighting her father's opponents they had practically always been men... or monsters. To challenge her own sex and to win, somehow it meant more even after all this time. There was just something about fucking another woman that made her feel so wonderfully powerful and dominant.

Nebula enjoyed the Pained-pleasure on the Terran's face just as much as the sheer concentration on her sister's as she thrust into the helpless girl. They were a perfect trinity; a combination of green, blue and pink flesh all flushed together. A mass of perfect jiggling flesh working in harmony. Nebula had always known she was sadistic, cruel. But seeing her goody-two-shoes sister revel in the same depravity? It was too delicious, bringing Gamora down to her own level.

Natasha tried to keep breathing once the assassin increased her pounding but it was no use. In what felt like less than a second her pussy was clenching tightly around the large invader and she was covering it with her cum, pure ecstasy shuddering through her body as she experienced her first climax that night. It was of course followed by another, and another, and another, the captivating alien pounding her pussy to orgasm after orgasm.

Natasha closed her eyes: had she been wrong to trust Gamora? What if this were just a game? Natasha shuddered, lashes fluttering as her supposed Guardian's powerful penis plowed into her sopping nethers. If she didn't stop soon, either her body would give in to this pleasurable torment, or her mind would.

Arching feebly, Natasha did her best to accommodate both phalluses, allowing Nebula's shaft to plunge another inch down her throat while Gamora's stretched her vagina. And with every pump the strange liquid gathered around her, inflating her mouth and pussy, making her oh so hot and horny.

Gamora could feel the girl fading, only just managing to float between them on the surface as their cocks speared into her from both ends. She had to distract Nebula:

Leaning forward fast, Nebula had no time to react before Gamora's lips were on her own, her sister pressing her mouth to the surprised warrior's. Laughing into the kiss, Nebula deepened their embrace lustfully, no longer interested in the human sandwiched between them as she tasted her sister once more. For Nebula, such an act of intimacy was childish but to kiss her greatest rival was the ultimate act of competition: And she got off on that.

While Gamora hated using herself to protect the human, this strategy worked perfectly and for over a minute Nebula was far too distracted by the kiss to harm the fledgling redhead. Meanwhile the blue woman bit her sister's lips, her tongue snaking deep into Gamora's waiting gullet.

Breaking away, Nebula cackled mirthlessly, throwing her hips into Natasha's face as she spoke:

"Ohhh sister mine! When did you get so sentimental?!?"

Gamora just scowled, wiping sore lips as she thrusted instinctively back against the poor redhead.

Below Natasha was spit roasted brutally; while Gamora simply rolled her hips, massaging her aching pussy, Nebula pummeled her mouth, sending the redhead back and forth between the two dildos.

Even in her already impossible situation, Natasha knew there was simply no way out; the redhead couldn't exclaim, couldn't even pull backward without further impaling her sore pussy. The humiliation was unbearable, trapped between two aliens, her throat distended, her pussy throbbing with unbearable pleasure: The antithesis of subjugation.

And through it all Natasha found herself moaning around the cock in her mouth, her already well fucked pussy ready to come again as the women above her fought for control, both slamming their respective phalluses into her weakened body only to coax further pleasure from the disgraced Avenger.

"We should finish her," Nebula stated coldly, even as she pulled the redhead down onto her dildo even further, making Natasha's cheeks bulge.

"I'm not done," Gamora growled back, thrusting into Natasha's already stuffed pussy.

"Dad always taught us not to play with our food," Nebula responded dangerously; tugging the human toward her once more, oil spraying out around her hips.

Natasha came again, her frame convulsing between the two sisters. There was no love, or even encouragement as she was attacked on two fronts; her body well and truly fucked:

"Bored now!"

Suddenly Nebula pulled away, taking the other two women by surprise.

With nothing in front of her to hold the redhead up, Natasha sank into the liquid with Gamora close behind. Spluttering Natasha tried to get her bearing, exhausted as she splashed to lift her head up.

"You think you can squeeze more enjoyment from the Terran, go ahead," Nebula goaded, crossing her arms:

"Otherwise kill it."

Snarling back at Nebula, Gamora rolled the redhead over, seeing defeat in her glazed eyes.

"Get up," the assassin mouthed to the human, concern flashing over her own orbs as she stared down at the ailing human.

Floating in the pool Natasha was limp, gurgling the liquid with her own eyes half open, lost in a sea of pleasure and oil Seeing Gamora's fearful expression, Natasha knew she would have to test the limits of her own endurance, or face even greater consequences. She had to act like this wasn't getting to her, that she had more to give.

Smiling weakly Natasha floated on her back, glancing over at the blue alien before turning her attention back to Gamora:

"Take my ass."

Gamora nodded; this display might just keep Nebula entertained. Sliding her fingers through her long wet hair, the alien swept it back; ready for battle.

Pulling herself up against the rim of the pool, Natasha spread her legs invitingly, raising an eyebrow at the strange sisters as she drew a shuddering breath:

"Take it!"

Nebula smirked; this should be interesting.

Stepping between the redhead's thighs, Gamora made a show of taking possession of the human, proving she was the stronger sister. Natasha had challenged her and she would take possession. This was still the best outcome: Given the opportunity Nebula would still pounce.

"I hope you're flexible," Gamora muttered, sliding a hand beneath the human's behind.

"yeah," Natasha whispered, eyes darting back to the blue alien before meeting Gamora's once more:

"Me too..."

Swiftly lifting the redhead's thigh, Gamora didn't stop until the woman was bent over, her ass raised tantalisingly out of the liquid. Braced against the pool's rim, Natasha swallowed, her head now practically between her knees. Resting a leg on her shoulder, the alien finally looked down at Natasha's exposed nether regions.

Pressing forward, Gamora leant over the inclined human, stretching Natasha's legs even further. Natasha groaned, feeling her cheeks stretch apart under the insistent pressure, her feet now well above her.

Kissing the inside of a long leg, Gamora sensed her sister watching haughtily. Keeping up the pretense, she suddenly bit into the girl's smooth flesh, leaving a dark red mark. Natasha gasped, swallowing the pain. Nevertheless, this aggressive act seemed to satiate Nebula, at least momentarily.

Sliding her dildo against the redhead's behind, Gamora adjusted her stance, positioning the massive phallus. Surveying the redhead's soft pucker, the brunette saw how the taught hole now dilated, oil rolling over her soft pucker, practically inviting her in:

How could a creature so soft invite such harshness? The woman that had pushed back a Chitauri invasion, now asking a strange being from another planet to fuck her ass! Was that weakness or strength?? Regardless, such a mentality was beyond her; physicality was fact. Natasha Romanoff was no match for the two sisters.

Teasing the woman's asshole, she slid her alien cock around tender pink flesh, Gamora occasionally pushing inside, helping to ease the submissive Natasha while testing her impatient sister. None of them could hide their anticipation. That was the gift of the pool; revealing hidden truths.

Nebula tensed, head cocked, watching curiously from the other side of the pool: Gamora wouldn't do it. She couldn't. She was too vanilla, too tame for such an act of degradation. And yet...

Swiping her hands across the rim of the pool, Natasha tried to stay calm, in spite of the dildo probing at her butthole. Breathing hard, the redhead wriggled against Gamora's unyielding shaft, sliding back and forth between her open cheeks. Tugging unkempt wet red locks from her eyes, Natasha held the alien's gaze, bracing herself for the inevitable.

Nebula smirked as her sister pressed forward, watching her hips slice into the human's pale behind. Licking her lips, the blue warrior watched in appreciation as Gamora easily opened the redhead's sphincter, using the lubrication of the pool to slide smoothly into the woman's behind.

Throwing her head back, Natasha bit her lip, struggling to hold still as she was speared onto the blunt phallus, wrapping her legs around her protector's abdomen as she was cruelly invaded. Closing her eyes, Natasha embraced the sensation as her rectum was plugged, feeling the pressure build as it continued into her body, not stopping until Gamora's cheeks met her soft behind:

"Ahhh!"

Feeling the hilt collide with the redhead's bottom, Gamora smiled in grim satisfaction, allowing the human a few moments to grow accustomed to the shaft buried in her butthole. Feeling her sister's stare burning into her back, the green alien began moving once more.

"Ohhhh!" Natasha gasped as the phallus was withdrawn, eyes wide as she was hit by a new, unexpected sensation. With the dildo sliding free, the surrounding liquid rushed to fill the vacuum that it left, her body practically sucking in the strange oil in its absence.

Screwing her eyes shut Natasha realised she could no longer evacuate, Gamora practically pumping her full of the syrupy fluid. Feeling helpless the redhead clenched her belly, hoping to resist the pressure that persisted with each stroke of the blue alien's hips.

Gamora watched expectantly as the bubbles began to rise from between the two women, popping on the smooth surface and tickling her abdomen; she knew Natasha couldn't handle this.

A second later she was gasping once more, Gamora holding her waist as the redhead was persistently pumped, each motion sending a swell of liquid into her already full colon.

It was so bizarre and intense Natasha forgot about her larger predicament, eyes locked onto Gamora's dark orbs as her own green iris' grew impossibly wide. Quivering in shock, she felt the liquid pour into every crevice, her insides cramping as the alien increased her pace, the assassin's strength soon pounding the redhead into submission, the mix of weird pleasure and painful pressure becoming unbearable.

Overcome by her submission Natasha yelped, swaying in the waves the alien made on every thrust through the unnatural liquid:

"Unnghh! Mmmm, mph! Unngh ugh! Uh! Uh! Ahhh!!

Watching the human squeal, each unprompted outburst widened Nebula's grin. Unfortunately Natasha; some torture's were far too enjoyable for her not to join in.

Only a truly skilled lover like Gamora could make a being beg for mercy when they inundated with pleasure and this Terran had completely failed to hide how desperately she needed to cum. of course her uptight sister would usually never allow for such a humiliation; until now. That was what drew Nebula in.

Pulling the phallus back, Gamora paused as a cold metal hand landed on her shoulder. Nebula took a moment to enjoy the groan of agony from the pathetic Terran as her anus sucked at the shaft needily, before calmly asking:

"Who are your Masters human?"

Gritting her teeth Natasha scowled; She was compromised, she had to respond. Opening her mouth, the redhead replied grudgingly, swallowing her frustration:

"You are."

"Elaborate," Nebula barked.

Looking between Nebula and Gamora, Natasha saw the compassion in the green alien's eyes and the contempt in her sister's. Making the subtlest of movements, Gamora nodded to her to continue.

"You are my Masters, our Masters. The human race is yours." Natasha stated hollowly, eyes fixed hopelessly on Gamora's. The green alien sighed in relief; she may have just saved this Earthling's life.

Then Nebula grasped the redhead's throat, Natasha flinching, her eyes meeting Gamora's once more as they widened desperately: