Fic: The Stress-Strain Curve (Uhura/McCoy)

[shinychimera.livejournal.com]

Title:
 The Stress-Strain Curve
Author: shinychimera
Fandom: AOS (works as TOS, too)

Characters: Nyota Uhura, Leonard McCoy
Rating:
 NC-17
Warnings: Anal play, if you're not into that; explicit and kinda kinky.

Word Count: ~3,800 words

Summary: You have to understand a person well before you know how far you can bend them without breaking them, and McCoy knows Uhura very well.


Notes: My deepest thanks to rubynye for a much-needed beta!

While helping my best friend and frequent co-writer yeomanrand brainstorm on igrockspock's prompts for the WNW New Year's Exchange, I came up with an idea for this lil ol' PWP story. Rand pursued a different (and surely more substantial!) idea, and I tossed this one onto the "someday" pile. Then Rand got some unhappy news, and I returned to this idea to write her a porny "feel better soon" story -- so now it has become a "cheer up/holiday/new year gift" for her and a "thank you for being an awesome organizer/bonus exchange fill" for igrockspock. :)

Enjoy, my dears!

Note: Hover over non-English words to see a translation in the title text.

---

Nyota leaned against the back of the turbolift, keeping her eyes on the flickering lights so that she wouldn't fall asleep on her feet. Her muscles felt heavy, her spine as stiff as a petrified tree.

For nearly three days now, she'd spent every waking moment hunched over her console trying to figure out what was missing from the translator algorithms for the Ojoxe. Their first two meetings had been disastrous and though the representatives seemed to know misunderstandings were in play, they were growing increasingly frustrated with the Federation's inability to parley. If she couldn't crack this problem, the captain would have to order a retreat from the planet until other specialists could be brought in — and she'd be damned if she let that happen on her ship.

Still, she conceded, Kirk had been right to order her off the bridge.

She suddenly remembered the bending arch of a stress-strain curve from an Academy engineering class: the measure of just how much load a material could take before it suddenly compressed, bent — or shattered.

Nyota sighed when the lift came to a stop, and made her way down the empty corridor. The door to her quarters slid open at her touch but she entered slowly, hearing an unfamiliar muted thunder from her bathroom. Incredulous, she convinced herself that yes, she was hearing water — real, running water — filling the tub she'd never bothered to slide out from the back wall of her sonic shower cubicle.

"Comin' in, darlin'?"

She smiled and walked toward the voice, pulling out the clasp that held the textured curls of her current hairstyle in a high poufy ponytail. Her scalp ached with released tension as she shook free the hair that billowed almost to her waist.

"Wow...a real bath."

"Doctor's orders," Leonard said, smiling up at her from where he sat on the edge of the bathtub, testing the temperature of the running water with his fingers. His dark hair, normally so orderly, was still rumpled from where he'd stripped his uniform off; he wore only a simple white bathrobe.

"Oh, are you my doctor tonight?" Nyota inhaled the warm steam, in itself a welcome relief from the starship's pure but dry recycled air, and leaned against the counter where he indicated. She let him lift her foot, watched him squeeze and stroke a firm hand up the leather over the back of her calf before he released the fastener and tenderly slid the boot off ankle, heel, toes.

"Only as much as I need to be to authorize a private therapeutic bath," he said. She spread her toes in pleasure when his thumbs rubbed hard around the tired muscles of ankle and arch, and his hazel-green eyes shone up at her. He reached for the other foot and repeated the process just as intently. Leonard really loved her boots.

"So...bath and sleep?" he asked. "Bath and massage and sleep?"

She tilted her head with a disappointed frown, long loose hair falling against her cheek.

"Ah...in the mood for more, are we? I wasn't sure you would be."

"I'm tired," she said, "but I need more than sleep."

"You need to take your mind off the problem for a while," Leonard agreed with a nod. He pivoted and turned off the stream of water, then stood and took her in his arms, waited for her to initiate a kiss and then returned it with warm enthusiasm. When they parted, he leaned his forehead against hers. "I have a few ideas, if you'll let me be of use."

Nyota smiled at his phrasing; even when he wanted to take the lead in their lovemaking, he liked to frame his request as worshipful service. "That sounds heavenly, mchumba."

"Good," he said, nuzzling against her cheek for a moment, then helped her to undress. "Just do me one favor, darlin', keep your hair dry — we don't have any proper shampoo for wet hair anyhow."

She nodded, and let him use a wide-jawed clip to gather the bulk of her hair into a loose twist on top of her head. He took her hand; she stepped in and sank down into the just-this-side-of-scalding water which rose almost to the edge of the tub.

"Ohhh," she said, water wrapping blissfully around her limbs, heat sinking right down into her bones.

"You soak for a while, and get yourself clean all over," he nodded significantly, "and I'll have my toys ready when you come out."

Curiosity quivered lightly for a moment, in her mind and between her legs, but she let her eyes slide closed and listened to him gather up her clothes and boots. She'd find out what he had in mind soon enough.

She allowed herself to simply luxuriate in the steaming water for a long time before she reached for the pristine bar of soap waiting on the corner of the tub, and she smiled at the blooming scent of the lather. Trust Leonard to remember, three years later, how much she loved the sweet autumnal smell of dragon's blood resin — or no, he had to have packed this back on Earth, hadn't he? He'd been carrying it around all this time, waiting for the right moment to warm her with such a vivid reminder of home.

Nyota washed herself thoroughly, enjoying every moment of the water on her skin; she used the soft towel he had left for her to pat dry the droplets on her hair and body, then made sure her nether parts were as clean and fresh as the rest of her. Her vagina was eager and wet, and she drew her juices up along her labia and clit to chase away the dryness left by the perfumed soap. Her own scent mingled excitingly with that of the dragon's blood.

When she emerged, the bedroom was comfortably warm and she saw he'd dimmed the lights and folded her bedding down, exposing the flat expanse of the sheet. Their favorite versatile cushion rested on the floor by the side of the bed, and he waited there on his knees, naked and beautiful. She never tired of his sweet lips, his broad shoulders, the triangular patch of hair on his chest that poured a dark line down his belly to the thicket that curled around his eager cock.

Leonard stood, banked desire burning in his eyes as she walked naked across the room. He reached for her hand, guiding her to kneel on the bed facing the wall, then he slid up behind her and nuzzled beneath the coiled hair at the nape of her neck while his hands slid up her sides. His lips found the soft skin beneath her ear just as his hand closed over one small breast, stroking and caressing until he squeezed upwards, fingers sliding until all they held was the nipple; its soft mounded shape rapidly changed to a tight fingertip nub of pleasure.

She tilted her head back, loving the way he woke her skin and erogenous zones in stages, layering gentle touch and teasing fingernails with hard squeezes where muscle or flesh could bear it. He laid her hands on her thighs, pressed his own over them, stroked up and down the smooth skin using her own passive fingers as a tool for her pleasure. Finally, he nudged her hands up along her warm inner thighs, until her thumbs rubbed on either side of her vulva, lightly compressing the clitoris hidden in the depths of her swelling labia.

Nyota accepted the tacit guidance to continue this slow, muted pleasure while he leaned down to pick up her hairbrush, then pulled the clip from the top of her head and fluffed the voluminous hair loose. He began at the ends and brushed slowly, firmly through the most recent light tangles: forty, fifty strokes until the black mane almost floated around her head, neck, and shoulders. He loved the thick natural texture of this hairstyle almost as much as he loved her boots, and hair brushing was a gentle pleasure they'd shared before — but never in a way as overtly erotic as this. She found the prickle and tug of the brush almost unbearably sensual when combined with the growing throb between her thighs.

Leonard picked up a length of supple red cord, folded it in half, and held it with a couple of fingers while he gathered and divided the back of her hair into three chunky ponytails. She pressed her thumbs together more firmly, building her arousal, a little surprised by his detour but trusting she'd enjoy the destination. He fussed a little while over getting the braid started to his liking, with the center of the cord threaded through the base just so.

"Tuck your chin down, darlin'," he murmured, and she exhaled, closed her eyes, and surrendered to his quick, knowledgeable hands. He pulled the three sections taut and began tugging and twisting in earnest, compressing and separating and re-separating the hair as he went.

Sensations tickled against the small of her back with each motion of his wrists — he was weaving the dangling ends of the cord into the wide braid alongside her hair. He slowed as he reached her lower spine, tied the ends of the cord in a careful knot, then gave the braid a good tug.

"That hurt at all?"

"No."

"Good."

Leonard lifted the braid over her shoulder, and rubbed thumbs and palms across her shoulders and bent neck in the way that always made her groan. Her eyes slid half-open, but she barely noted his handiwork, the short arcs of the cord glowing vivid crimson among the black plaits, because of the way his fingers and lips nuzzled against her skin.

"Bend down, sweetheart, stretch your hands out toward the wall."

She obeyed, bemused — stretching out like a cat, hunching her shoulders forward and then rolling them back. He pressed thumbs down along her upper back, slowly making sure the strong muscles were equally relaxed on both sides of her spine, but the lower he went the less clinical his touch became. It wasn't a massage by the time he reached her waist — it was pure lascivious praise in fingertip form. His hands curled around her curves like they'd been made to fit, and her skin sang where he touched.

A light hand on her waist was all it took to nudge her back to a kneeling position, and turn her to face the room; her hands dangled at her sides and her knees spread wider of their own accord, her body aching for a more intimate touch. The brief absence of his caresses was more than excused by faint pop of a lube bottle opening. One of Leonard's hands slid down her belly, holding firm against the soft swell above her pubic hair, while the other mirrored it on her backside, compressing her abdomen deliciously. A lip-dragging kiss, then his hands slid down in tandem, slick middle fingers parting labia and buttocks without letting up on the compression, and he reached clitoris and anus at the same time.

She gasped in ecstasy, pelvic muscles flexing and fluids flowing as he played her, flicking and fluttering against her fore and aft. She thrust her hips up and down, hardly able to decide which stimulus she wanted more; in the end she leaned against his arm, pushed her rear backward, spreading her cheeks wider. Her clit was fully awake, swollen and throbbing, but she could never get enough anal play. Her sphincter was sometimes as sensitive as her labia, quivering in response to pressure from either inside or outside the hard ring of muscle that clutched greedily at any penetrating force, and she loved the sensation of being filled and overfilled, feeling that pressure against the tight walls of her rectum whether or not there was anything providing counter-pressure in her vagina.

As her lover, Leonard took delight in offering this pleasure to her, and as her doctor, he could ensure their frequent play never injured or stretched the delicate tissue — her pelvic floor was as tight and toned as it had been when she was still a virgin ballerina.

He drawled dirty nothings in her ear, knew exactly how to tease and tickle the tender pucker of her anus, spreading lube from tailbone to perineum and rubbing in spirals until she sighed, pushing herself wide to engulf the end of his finger.

"That's it, darlin'," he said huskily, probing shallowly, twisting and stretching.

She grunted and groaned encouragements, and then complaints when the fingertip withdrew — but it was soon replaced by a polished metal bead of about the same size. She accepted it eagerly, even more so when he pushed it in deep, and she felt another bead nudging at her entrance, a little larger. His other hand cupped her vulva, middle finger tucked into her wet labia, and she squirmed against the pressure while he continued; he let her savor the moment when her sphincter stretched widest, and then closed again around the smooth strand that held the half-dozen increasingly large beads together.

Nyota was panting, more than ready to pull him down onto the bed and fuck him blind, but he pressed the next cool bead on the strand into her lubricated hole, and she wriggled in his arms as she stretched wider, wider. She knew the sphere likely wasn't more than a couple of centimeters in diameter but it felt enormous — and, once she swallowed it into her depths with an involuntary gasp, she realized it wasn't just a round ball. She felt it tapering, a rigid elongated teardrop that he kept pushing further and maneuvering deeper, until she realized the bead was only the tip of an elaborate, lyre-shaped hook.

She felt the fat teardrop tip curving into her rectum, pressing toward her belly from the inside, while the slender stem curved out of her and up between her buttocks, cradling and then curving away from her tailbone. She clutched his arm where it propped up her torso, struggled to imagine what the hook looked like to him, felt the pressure inside mounting pleasure on pleasure.

"Now..." he crooned, sliding his hand up off her swollen labia, over pubic hair and navel, tracing wet fingertips between her breasts up to the notch of her throat and over her windpipe. His fingers brushed beneath her chin, and her face tilted to the ceiling; his other hand stroked down the length of the braid, and her spine curved back.

Something caught, and sudden tension thrummed through her frame. She jolted, and the smooth curves of the hook buried in her body jerked and tilted, shoving hard within her.

She made an incoherent noise, and tried again to straighten — and again, her body shook and strained, pleasure pressing weirdly against her sensitized anus, tugging painfully on her scalp as the braid pulled it back. Her spine made a bending arch, held by her own hair, wrapped inextricably around the cord pulled taut between her scalp and the deeply embedded hook.

Nyota gasped, eyes wide and throat vulnerable and exposed, and she tilted her head back just a bit to ease the sharp pull on the roots of her hair. Balance, balance, her mind gibbered; she had to find a balance between the piercing pleasure and the potential pain. Leonard's hands rested on her shoulders but she had no idea if he was watching her, talking to her — every fiber of her consciousness was focused inwards.

She moaned, overwhelmed by what he'd done to her, and flexed her pelvic muscles experimentally. She felt the polished metal inside her — warm now with her body heat — shift and tug, snugging itself firmly within the sensitive stretch of her lower rectum. She could no longer feel the beads that had gone first, knew she would only become aware of them again when Leonard drew them out of her.

She clenched again and shuddered at the probing fullness, pressed right where she liked it, which — who knew her body with more precision than Leonard did? She knew, then, that he'd had this toy custom made for her.

Groaning and grimacing, she tugged her chin down again slightly, stretching other muscles until she found that balance in a slight rocking of her pelvis, shifting the hook against the constant upward drag of her reinforced braid. In and out, just a little at a time, the tapered stem of the bulbous teardrop slid through her slick anus, teasing her with the gaps between sensations.

The gaps...

Her mind was filled with chaotic flowing images, the answer to the translation problem glowing at her through the gaps between his fingers, the gaps between words...

And then Leonard's mouth was on her bent neck, startling helpless cries from her, and her flinch rammed the hook upwards within her again, jolting her pleasure centers at the same time that the distributed pain cascaded mildly across her scalp, down her curved spine. Her fingers twitched open and closed at the end of writhing arms; his lips trailed downwards and caught at her hard, tingling nipples. Trying to brace against the pleasure that seethed beneath his tongue sent shudders of pain-fraught tension through her — her only choice was to go back to her gentle rocking, letting his stimulation become part of her rhythm instead of shocking her out of it. Thrusting and pivoting her thighs and hips sent jouncing stress through her in waves.

She heard herself cursing and crooning: she was bizarrely poised between being fully in control of her own pleasure, and captive within her own body beneath his touch. His tongue flicked and circled her breasts, leaving coils of wetness cooling on skin hungry for more and more, and she couldn't see him — only feel him sinking down to his knees on the cushion by the side of the bed, hands holding her cambered ribcage, dropping the sloppy saliva trail to her navel and beyond.

Her aching thighs spasmed and spread, shifting the hook again, magnifying the pressure she felt through the walls of rectum and vagina, right up against the inside of her pubic bone where clusters of clitoral and urethral nerves fought for primacy, and now the fake, phantasmal urge to pee was laid over the rest of her increasingly clamorous pleasure, and his purposeful mouth hadn't even reached her—

"Gaaa-haahhhh!" she shrieked.

Only the firm hands on her waist kept her from collapsing backwards, overbalanced. Leonard used his tongue softly against her vulva, starting with broad, slow swipes rather than delving after her clitoris — he surely knew how overwhelmed she was. Her fingers found a home in his hair, knotting and unknotting against his scalp, and she stared unseeing beyond the soft glow of the lights on her ceiling.

"Good lord, Leonard, shetani mchumba," she started, voice rising swiftly from a throaty mumble to a wild cry, "mo ghrá, veh shan'hal'lak, bozhe MOI, ai-YAAAAAH....!"

But he wouldn't let her disintegrate yet — soft and considerate, his tongue was, but also relentless. Gasping harder and harder, a contorted puppet, she had to find a new rhythmic balance, letting his hands hold her up as her muscles drove her pelvis like a rotor, back and down against the hook, forward and up against his tongue, aching tension growing worse with every minute but overlain with phenomenal compounding pleasure.

You should get to fuck me after all this, she thought, sobbing ecstatically, breathless even in her thoughts.

But she didn't want a cock just now, and he seemed to know it — he made no move to lift his face from her lap, just supported her lower back and drove her wild with his pointed, probing tongue.

Thrashing, she held his head tight, cries building into continuous, warbling song as unbearable sensations built and crashed outwards from the clit throbbing beneath fervid, swollen labia, from her asshole stretched and filled with thrusting heat, from her vagina seeping with sweet lubrication. Searing ecstasies rocked her helplessly, and still he didn't stop, spurring her towards an orgasm like the crash of a thunderstorm, bone deep and messy and wet.

Swimming in the smell of dragon's blood and sex, she felt his hand on her waist twist and yank, felt the tension suddenly release from the cord and free her braid. Her head whipped down, pulling her spine and body up out of its unnatural arch, and his head came up out of her crotch so that he could catch and hold her as she shuddered and moaned. She caught a brief glimpse of his luscious lips, shining wetly in the lowered light, before she collapsed against his chest.

After the floods of pleasure had faded, and the sharpest of her pains, Leonard climbed into the bed, shifting and easing her quivering body forward so that she curled over her still-folded knees; her spine bent in a new curve that countered the old one, helping her body to recover from the stress. Her joints and muscles settled into comfort one by one as he stretched her limbs out flat and caressed loving fingers down the knobs of her vertebrae.

Then he touched the outer flange of the hook that now felt so much a part of her. She flexed her internal muscles so he could feel the body-warm metal shift in his hand; he murmured appreciatively. Satisfaction spread through her in lazy ripples.

Lying on the bare sheet, Nyota felt shapeless, sleepy, thoroughly relaxed, and Leonard started singing one of her favorite soft Southern lullabies, tenderly tugging on the hook. She resisted the urge to push; she didn't want to expel it all at once in a burst of stimulation — instead she floated with her eyes closed, savoring the slow stretch of sensation as the increasing diameter of the shaft dilated her anus in a steady, gentle slide. Too lost in her feelings even to let him know it, she breathed deep and even, riding the quiet and profound layers of bliss in the aftermath of tension.

She didn't need or expect the deep weary pleasure to do anything but drift her into slumber, so she was taken by surprise when her over-sensitive anus stretched around the widest part of the polished bulb, and the intense moment suddenly crested over into a silent, powerful second orgasm, radiant light glowing again through the meaning-laden gaps in her mind's kaleidoscopic images. The toy slid free of her body in one swift purge, and several dreamy aftershocks followed, as Leonard coaxed each of the smaller beads up to and out of her delicate hole in turn, so slow and satisfying that by the time the last of her tension was gone, Nyota was sound asleep.