A Sister’s Love [Black Widow]

Summary: Natasha and Yelena were thrown into the Red Room and trained for years, turned from children to assassins. Near the end of their training, both are given highly experimental, aphrodisiac-based drugs that turn the caring, loving sisters into incestuous, lovers. Oh, and Yelena grows a cock.

Content Tag: Incest, Futanari, Rough Sex, Pregnancy, Drugs

-x-X-x-

"Again." Yelled Natasha's instructor, watching as the redhead breathed with a dry throat, coughing specks of blood on the floor as she struggled to stand back up. She faced her partner- a woman older and far stronger than her. She ducked and kicked, keeping her arms close to her body. Just like she was trained. Each movement led to a string of attacks lethal to most people, but not for her opponent. This woman was agile, with no shortage of takedown methods. She could handle Natasha and that pissed her off. She threw punches, but they all missed.

They always seemed to miss this woman "Come on now. Your coronation is coming up soon. You won't pass with this sloppy form." Of course. The thing that's been in the back of her mind for what feels like years now. When she turns a certain age, she is to have her skills tested by unseen examiners. She had nightmares about it. It was held in an all-red room, with one-way glass lining the walls. She wouldn't know if she was being watched or ignored once she entered that room. The only thing she did know was if she passed, she was a true assassin.

Her tormentor of a teacher then swept her legs, knocking her down to the ground as she felt the older woman's knee on her chest. Natasha grunted and attempted to lift it, to no avail. The overseer waved her hand and let the redhead go, watching as her student coughed even more. "Get yourself cleaned up, then head to your room. We're done for today." Natasha picked herself up in shame and walked towards the door, limping out as she passed by her colleagues; they were about to experience what she had just gone through.

The beaten and battered woman took to her room, licking her wounds as she took a much-needed shower. They were instructed to take one no longer than five minutes, making it something she looked forward to. She was given the privilege of warm water, a moderately comfortable bed, and food on the table. All they asked in return was her loyalty and total obedience. It was a freedom that no woman had, but no one could imagine breaking away from this life. Abandoning it would court death and guarantee a shortened lifespan. Any one of the women she lived with could've been the one to fire the final shot.

After her shower, she took off her towel and put on the loose-fit pants and white shirt given to all members of the red room. She wasn't given any underwear- that was for missions within the outside world. She sat on the bed, resting her face on her palms as she stared at the bare wooden floor, contemplating how poorly she'd done today. She never did this poorly, not when something this important was on the line. She clicked her tongue, rolling it in her mouth as her eyes glazed over. She couldn't see the floor, or register what she was doing.

The night turned a blackish blue as she finally snapped out of it, looking at her clock above the door. It was nearly eight o'clock. She drank her saliva and laid down, closing her dry eyes as her exhaustion finally caught up with her, the adrenaline now long gone. She had a recurring thought on nights like these, like a circle of reasons for why she was here. Most of these thoughts led to her blaming her mother, others told her that all of this was somehow her fault, with a tiny voice in the back of her head saying a rather troubling thought: you deserve to be here.

That alone scared her more than anything else. That their brainwashing was working and she was believing in their lies. She had to stay strong, for herself and Yelena, wherever her sister was. She didn't think about her as often as she used to. She never saw her, or even heard about her. All she knew for certain was that Yelena was alive, being trained to be a cold-hearted killer. Natasha didn't seem to care now, only focusing on what she could do to get as far away from here as possible. That's all she cared about.

The door then burst open, startling the redhead as she stood up, fists in the air as the doctor stepped forward. "Ah, glad to see you're awake." He spoke, each word delivered in a devilishly intricate way. He was as dangerous as he was intelligent. He only appeared like this when it was important "It is time." He told her. She looked at the clock, now realizing that it was set at a faster speed than any other clock. It was now twelve ozone when it was eight mere minutes ago. This was a way to hide when it would happen.

She didn't speak as she walked over to the stretcher, breathing in as she was strapped down and moved through the corridors. The right wheel squeaks and makes sharp high pitched noise with every turn. It was another way of getting into her head, seeing if she was ready or if she was to be put to death. Or she was being dramatic, they were pretty deranged. Maybe they enjoyed the eye-gouging sound? Certainly wouldn't be out of character for them. They've cake at girls puking on the mat while being beaten to near death. They thrived off everything evil.

It wasn't long until she reached an open door, with one light source emanating from the middle of the empty room. She closed her eyes, not daring to watch as needles were moved and tight gloves were put on. Her fingers twitched, her jaw clenched up as she stiffened her body. What would happen next may be the last decision she made for herself. The doctor laughed as his assistant helped administer a clear, yet thick substance. He stabbed a needle into her arm, with the others being shoved into her leg, then neck until around a dozen or so shots were given to her. But these weren't the ones she was used to.

The normal ones lasted no more than a second and gave her a small bruise, but these took forever to be given to her. Her mind felt dizzy, her nose couldn't stop sniffing as her body struggled against the restraints. What had they done to her? What did she allow them to inject into her? They looked at their watches and quickly moved her out of the room and towards the Red Room, something that made Natasha's stomach churn "Wh-What's going on?" The first time she's spoken in hours. They looked at her with a blank stare and opened the large doors.

She was dragged into the room, the doctor almost immediately walked out as his assistant unlocked the straps, giving Natasha a look as she was left alone. Or at least, she thought that she was left alone. She slowly stood up, her knees shaking under her weight as she heard crying on the other side of the room. She lifted her arms, expecting a wild animal, or a faker pretending to cry to lower her guard. But once her eyes adjusted to the red-tinted lights, her breath was taken with one word "Yelena." She said, her eyes widening as she quickly froze in place.

Her sister sat on the ground, naked as the day she was born. The poor girl was crying her eyes out, shaking like a wet dog as she looked up at her older sister "Natasha?" She croaked, relaxing as she took a deep breath. The young woman quickly kneeled to hug her, tears welling up as she wrapped her arms tightly around the young girl. "I-I can't believe you're here." The blonde whispered, keeping Natasha close as they pressed their foreheads together "I didn't think I'd ever see you again." Natasha opened her eyes, looking down as she noticed a weird shadow in between Yelena's legs.

"What's that?" She asked bluntly, her nose coming to life as she tried to cover her mouth "What did they do to you-?" She gasped, feeling her body begin to squirm as Yelena opened her hairless legs, revealing an appendage that wasn't supposed to be there "They…they gave you a dick?" She breathed, staring at the uncoiling mess of meat and hair. Yelena breathed heavily, now crawling on all fours "They took me hours ago, stitching and giving me these weird drugs! I didn't know what was going to happen!" Her dick dragged along the ground, growing thicker and longer.

Natasha took a few steps back, leaning back as her sister loomed over her. The small petite blonde moved her head closer, sniffing Natasha's face as sweat droplets fell onto her sister's face "You…smell nice." Innocent words, but it drove them to press their lips together, the world around them spinning as Yelena held her older sister. Her newly given cock sprung forward, laying on Natasha's stomach as the older woman lay on the ground. Whatever they did to her in that room, heightened her senses to an absurd degree. Every movement gave her agonizing arousal, with Yelena's cock making it a hundred times worse.

Grinning at Yelena, Natasha stripped off the t-shirt she was wearing, exposing her black bouncy tits as rge younger girl watched. Natasha then took her pants off, along with her panties. She liked the way Yelena's eyes were drawn to her body, it made her nipples hard; Natasha relished the feel of the heat coming off her dick as it nestled between her tits. The strong stench coming off it made her dizzy as she mashed her tits around her length. Yelena groaned at the feel of her soft skin rubbing against her dick.

It made Natasha smile again as she leaned her head down and brushed her tongue against the tip of her cock. Natasha watched her sister groan and bite her bottom lip as she rubbed her tits up and down faster. "Ahmmmph!!!" Natasha moaned, opening her mouth wide to take the top of Yelena's cock into her warm mouth. She could feel it pulsing in her mouth as she began bobbing her head up and down, taking him deeper down her throat with every motion. She heard Yelena groaning again and smiled to herself. Her jaw ached deliciously as she began working his length farther and farther down her throat!

"mmmmph, mmmph… sho bhiiig…" Natasha slurred, unable to form words correctly wound Yelena's cock. Her pussy was like a broken faucet now, trails of juices running down her thighs as her throat stretched around Yelena's dick as it reached down into her stomach! Yelena growled like a wild animal as she grabbed her hair tightly and pulled. Natasha squealed in pleasure, her pussy gushing suddenly as she came instantly! The drugs were making every bit of pain turn into undeniable pleasure. Nothing could calm her down! Yelena held her hair as she pumped Natashas head up and down. Natasha gagged and choked, but not in discomfort as she came again and again.

"Hugugh, guh, guh, mmmmmmmph!!!" she moaned, her eyes turning completely white as they rolled up in her sockets. Her hands gripped her sister, her nails digging into the teenager's supple skin. "Your mouth…it feels so good! " Yelena shouted at her, pumping her head up and down faster now. "Mmmmph!" Natasha screamed in pleasure, her tongue pressing against the underside of his cock. Natasha moaned in pleasure, tears rolling down her cheeks from so many repeated orgasms. Grinning, Yelena thrust so hard that Natasha felt herself black out in sheer orgasmic bliss as he filled her stomach with thick liquid warmth!

She reawakened in seconds, now bummed it was shooting directly into her stomach, not letting her get to taste any, but in the end, she didn't care. Yelena was fucking her, and doing every bit as good a job as she'd dreamed! "ahhhhh hah, aguh…" Natasha gasped when Yelena released her. She coughed up a bit of her cum, getting to taste it after all before swallowing it back down. Both of them took a moment to breathe, but not long as he was still rock hard! Smiling at Yelena, she moved to turn around, lifting her ass at him and spreading the soaking wet folds of her pussy with her fingers.

"Mmmmm, I know that's not all you got!" she told Yelena, "slam that huge thing inside me, I wanna still feel you inside me a week from now!"

Yelena only smiled in response, sitting up on her knees and grabbing her sister's ass in her hands. "I'm going to ruin your tight butthole!" She said, bringing her hands down to sharply spank her ass! Natasha squealed in ecstasy, her pussy gushing again as she used her fingers to spread herself as wide as she could.

"Hurry! Hurry up and fuck meeeeee!" she yelled, rocking her ass back and forth in wanton lust.

Yelena spanked her again, and Natasha let out an animalistic moan as she felt her cock pushing inside her. She'd never experienced anything like this! "oh yessss, so good! My pussy's so fuuuuulllll!" Natasha screamed, rocking her hips back and forth against Yelena as he began pounding into her like a jackhammer. "Mmmmmh, don't you dare hold back, fuck me! Pound my hole until you're the only cock that can satisfy me!!!"

"You're such a slut, Natasha…I like it!" Yelena said, spanking her again as she reached out to grab her wrists, pulling her backward as Yelena forced Natasha into a reverse cowgirl position.

Tears of pure pleasure ran down her face, she'd dreamed of this! "oh fuck, fuck yessssssssss!!" Natasha screamed, cumming harder and harder with his every thrust into her as she bounced up and down on Yelenas cock like some kind of sex doll. Her tits bounced in opposing circles. Yelena grunted loudly, slamming up into her over and over, her belly tenting to the limits every time. Drool ran down Natasha's chin as she panted for air. She couldn't think straight anymore, she felt almost numb from the waist down, aside from the maddening pleasure of his cock stretching her pussy to the limit.

Natasha couldn't even guess how many times she'd cum, but she never wanted it to stop as Yelena roared like a wild animal and she found herself face down on top of the bed as he sat on again. "You're all mine now, got it!" She said, spanking her ass once again.

"Yesssss…" Natasha agreed, "Please just don't stoooooop!!" she howled back as she felt him pushing his length inside her as more liquid warmth filled her. Yelena groaned in pleasure as she fell back onto the floor, pulling out her cock with a wet 'pop'. Natasha whimpered as she felt Yelena's cum pouring out of her, but she couldn't clench her inner muscles enough to keep them from falling back out of her body.

Lying on the floor, Natasha panted hard; she couldn't begin to guess how many times she's cum just now, but she wanted more! Natasha turned around and crawled on top of Yelena; "you better not be finished!" she told her, then yelped as Yelena grabbed her face and pulled her into a rough kiss!

"Mmmmh!" Natasha moaned into her lips, kissing Yelena's back with equal intensity, her tongue wrestling with Yelena's as she explored inside her mouth. She moved to straddle her waist, grinding her still gaping pussy against Yelena's throbbing erection. "Fuck my ass, now!" she told her, breaking the kiss and looking down at Yelena's red flushed face.

"Don't tell me what to do!" She roared back while rolling over, placing herself on top of Natasha again. She grabbed both of Natasha's ankles and lifted her sister's legs high into the air before spreading them wide. Natasha grinned back up at him as she pried open her ass cheeks for Yelena, then screamed in orgasm as her cock plowed up her ass in one thrust!

"Oh fuck yees!" Natasha screamed, her head leaning back as she panted in a mix of pleasure and pain. "My ass! Ahhh my ass is so fucking full lull, I love thiissss!" she screamed in orgasmic madness as she rubbed one hand furiously at her pussy as Yelena smashed her cock into her ass again and again.

She watched in awe as her stomach tented up and down with Yelena's cock as it moved back and forth. Her tits jiggled and bounced wildly with every slam of Yelena's hips into her ass, "big, big, so fucking biiiiig! Pound my asshole; mold it to your cock Yelena!"

"Natasha, you're…so tight!" Yelena yelled, slamming into her harder with every word.

"yeessssss, I am tight! I'm a virgin! You're taking my virginity!" Natasha agreed, cumming with the confession and chewing on her lower lip as she came again, and again, and again without end. "I love this Yelena! I love your big cock inside meee!"

Hooking her knees around his waist, Yelena grabbed Natasha's heavy jiggling tits and squeezed them roughly. Twin geysers of excess milk erupted from her nipples, clearly a side effect of the injections. Natasha screamed again in pleasure, loving the feeling of her tits being so roughly handled as the blonde teen leaned down and wrapped her mouth around one large pink nipple. "yesssss, milk me, milk my titss!" Natasha moaned, cumming even harder now as Yelena moved from one tit to the other and back again, gulping her milk down enthusiastically. "Yelena, ahhh, Yelena, yessss!" Natasha screamed at the top of her lungs as her hands clawed at the floor.

Distantly she heard Yelena groaning as she came inside her again, but Natasha already felt herself beginning to blackout with pleasure. It wasn't long until she came to, resituating herself so that Yelena was sitting down and Natasha placed her chest on her younger sister's lap, wrapping her massive breasts around the underaged futanari as she worked her tits up and down. Yelena slowly reached her hands out to grab those huge tits, loving how they felt around her fingers as she gripped them tight. "Mmmmh! That's the spirit, now squeeze them hard!" she moaned as Yelena pressed her tits tight around her throbbing erection. Groaning and cursing to herself as Yelena began pumping Natashas tits up and down.

"Yeah, like that, don't stop!!!" Natasha moaned, "oh yesssss, fuck my tits, Yelena!" Natasha screamed, "Mmmmmh you're gonna make me cum!" she squealed as she wrapped her arms around the thickness of Yelena's cock, pulling it to her mouth and taking the top nine inches into her mouth. "Ahhhh, Natashaaa…" Yelena groaned, loving the warm wet feel of her tight little mouth. "Mmmmph, sho yummyyyyy, I wuv bhig phick cawks in muh mouph pusshy!!" Natasha slurred around Yelena's dick. "Mmmmph, gugh, mmmmph, gugh!!" she moaned and gagged as she took him deeper into her mouth every time until her tits finally fell away from Yelena's cock as she deepthroated her entire dick!

She then grabbed Natashas hands and moved them to her head. Yelena then grabbed her head tightly and pumped her hips back and forth hard. Natashas eyes turned almost completely white as he saw her eyes roll back in her head. "Aatashaaa… I, I can't…" Yelena groaned. "yessh, cummmmm, cum in muh mouph!! Pheeed me cuuum!!" Natasha begged, her mouth licking and slurping around his cock every time she pumped her head up and down. "gugh gug, gug, mmmmmmmmphhhhh!" Natasha choked around his cock, then moaned as he began cumming in her mouth. Grunting in pleasure, Yelena released her grip and fell back against the ground, looking past Natasha to look at the one-way mirror.

The audience behind the mirrors smiled, clapping as the doctor gave a little bow. "It seems we have a success here doctor." One of them said, patting him on the back as they exchanged handshakes "It certainly was difficult. But, I believe the drug can be turned into an airborne weapon. If two sisters are driven to such passionate lovemaking, then I doubt anyone else could resist the effects." One person looked at Yelena, raising an eyebrow as he turned around "And giving that one a dick, was that part of your master plan?" The doctor simply shrugged in response.

"I thought it would make things more interesting, and it turns out I was right!" he chirped, acting as if he didn't do anything wrong. The group laughed and decided to leave, letting Natasha and Yelena continue with their sexual endeavors for the rest of the night. Hours went by as they fucked like wild animals, unable to stay away from one another as they became addicted to each other's presence. Their smells and fluids filled the room as the fucked each other more and more. They changed positions on the drop of a dime, making their bodies stretch and pull as they treated each other like living sex toys, ready to be used and abused.

2 AM

"So big~" was all Natasha said as she moved her breasts up and down faster, making Yelena groan louder as she watched. Yelena watched as Natasha opened her mouth wider and took the top six inches of her cock into her mouth while her tongue cleaned the underside of her length. She slicked his shaft with her saliva as she worked to take more and more of Yelena's cock into her mouth. She watched as her throat swelled from her thickness as Natasha worked to take his length deeper.

"Yelena… ahhh… that… feels… so good…" She panted as she continued moving her body up and down. Her lips made wet smacking noises around Yelena's cock as she let out a low moan herself, vibrating her throat around her cock.

Natashas dark eyes looked up at Yelena as she let her breasts fall away from cock. She then began taking her length into her mouth inch by inch until her soft lips touched against the base of Yelena's dick. "Mmmmph, sho phiiiick…" Natasha moaned, her words slurred by Yelena's girth as she began pulling her head back up slowly, then moved back down, then up, and down, over and over… "ahhaaaa, Natasha, I'm…" she couldn't finish as her cock surged with pleasure and Natasha's eyes went wide with surprise before she was blasted off his cock. Her cum had filled her mouth and stomach as she couldn't keep up with the flow and was launched off.

"Gwaahh!!!" she grunted. Yelena barely had time to blink before she rose back up and smiled at her, wrapping her massive tits around Yelena's cock again and pumping them up and down as she continued to cum, the thick white fluid landing everywhere. By the time it finally stopped her face and tits were dripping with it.

4 AM

The lips of her pussy spread wide as he slid inside her. Yelena groaned at the hot wet feel of her pussy clenching around his cock. "Mmmh, so fuuuullll… ahhh, this feels so good Yelena… go deeper, deeper…" she moaned, rolling her hips slightly, forcing his cock farther inside, "ahhh, I… I thought… it would hurt more… but…. Mmmmmmh, more, push it in all the way!!!" she moaned, her hips moving faster now. She then screamed as her pussy gushed around his cock. Yelena nodded and pushed his length in deeper, watching as her belly stretched around her girth. The redhaired girl's eyes rolled back slowly as she moaned in pleasure. "ahhh, so biiiig, I… I'm cumming!!!! Yes!!! This is cumming!? I love it!!! More, make me cum more Yelena!!!"

"Natasha…!" Yelena groaned, pushing her length in deeper, loving the way it made her moan as her stomach tented around him. She grabbed her sister's legs, holding onto her thighs as she began thrusting in faster, her cock making wet squishing noises every time she pushed into Natashas hot little hole. The lips of Natashas pussy clung tight to her every time she pulled back as if Natashas cunt never wanted her to leave. "Haaaahhh, so good, so good, so goooood…! Don't stop, don't stop, fuck me!!!" Natasha moaned in ecstasy, her eyes rolling back as she panted for every breath.

"This feels so good, I love it- more!!!! More, more, more, more!!!!!!" Groaning softly, Yelena held onto her thighs tightly, as she then began swinging her hips faster, Yelena's thighs slapping against her ass with a loud smack smack smack sound. "ooohhhh fuuuck!!!!!!!!" Natasha screamed, her tongue lolling out of her mouth now as her eyes turned almost completely white as they rolled back in their sockets. Drool trickled down her chin as she panted even harder, her heavy tits wobbling in opposing circles until Yelena reached her hands forward to grab them. Yelena was careful not to squeeze too hard as he pinched and tugged on her nipples, making her moan even harder.

"Yes, Yelena, don't stop, pound my pussy more, please, make my pussy yours and yours alone!" Natasha panted, rocking her hips against Yelena's thrusts. Her pussy gushed with his every thrust inside her now, thoroughly coating Yelena's cock as she pushed in balls deep with every thrust.

"ahhaahh… hahhhaaa… yes, don't stop!" Natasha moaned as Yelena continued working her back and forth along with his cock. Her pussy clenched him tighter and tighter and Yelena bit her lower lip to negate some of her pleasure; she wanted this to go on longer, to hear her moan more. Natasha screamed in pleasure, her pussy gushing again and again.

Yelena pulled her close and kissed her hard, sucking on her tongue as she moaned with ecstasy into his mouth. Natasha leaned her head back in a silent scream of pleasure as he began pounding into her harder. The entire room was filled with the wet slap slap slap of their bodies colliding over and over. "N-Natasha… I'm gonna…" Yelena groaned as she began thrusting into her slower now, leaving his cock buried inside her longer. "yesssss, inside!!! Cum inside me Yelena, make me your woman!!!!!" she moaned.

"Natasha…!" Yelena groaned as she slammed her cock inside her again as she hugged her body close, her huge tits squishing against his chest.

"Yelena!!!! Ahhh, I love you!!!!" she moaned as his cum flooded her womb, filling her in an instant with the rest gushing back out around his cock.

The two of them held onto one another tight, with Natasha panting in his arms, her body shaking slightly for a couple of moments before she finally steadied the rhythm of her breathing.

Yelena pulled away from her gently, her cock sliding out of her with a wet squishing noise. Reaching her up, she touched her cheek and traced her thumb down her cheek "I…I love…you…" she breathed, her vocal cords were sore. Natasha squeaked happily, pushing her face against Yelena in another kiss as she hugged him tightly. She held the kiss for a long while before breaking away and resting her head against his chest.

Months Later

Since the test was successful, they let the siblings out of the Red Room, not bothering to reverse the effects of the drugs. They sent them to a faraway place, where the hilltops rose and fell across a vast plain of grass. They lived in a small hut, with Natasha cradling her heavily pregnant belly. "Yelena dear, can you grab me a drink?" She asked, smiling as the smaller blonde picked up a glass of warm tea from the table.

"Here you are Sis~" She teased, kissing her sister's forehead as she sat beside the older woman, admiring the redhead as Natasha looked at her.

"Something on your mind?" Natasha asked, caressing Yelena's face as the young teen touched her hand, moving it to her crotch as Natasha gave her a knowing look

"No rest for me huh? Even with the baby soon on its way?" Yelena gave a devilish grin and kissed her sister on the lips, with Natasha pushing her hand down the front of Yelena's pants; grasping her enormous cock as she pumped her hand up and down

"I can't do as much anymore, but I hope you get what you want out of me~" The redhead purred, yanking the blond's pants down as Yelena stood on the couch.

The hung teen stood over her wife, shaking her cock from side to side as she placed the tip of her trouser snake into Natasha's mouth, pushing it deep down her throat as she fucked her on the soft furniture. The older sister choked on Yelena's massive dick, grasping her sister's cute bubble butt for stability. "Ghhuukk, Muuppggg! Ghhoorppp!" She gagged, drool rolling down her chin and onto her white blouse as Yelena let out a low growl. The younger woman then arched her back, reeling her head back as precum was shot down Natahsas gullet. "Nnghhh! Yeah, your throat is just as tight as ever!"

Natasha gave a slurred giggle, feeling her throat stretch as the top of Yelena's cock went down her esophagus. She could feel her collarbone straining to keep Yelena's fantastic cock in one place, her breasts moving back and forth as the couch creaked defiantly. "Fuck, just like that!" Yelena purred, gripping the back of Natasha's hair as she suffocated her sister and started to drain her fat juicy balls down her older sister's throat. Natasha gulped air as Yelena sat back down beside her, snuggling next to her as her cock went limp. "I…love you…too…" She breathed, her voice was airy and her mind fuzzy as she relaxed on the loveseat with her adoring sister~ This was the life she never knew she wanted.