Open Up Baby
Title: Open Up Baby Pairing: Tony Stark x Female Reader
Summary: Tony Stark straps you into a StarkTech-compatible bench for a private demonstration of his newest toys- complete with biometric feedback,
Word Count: 3.6k
Warnings: / Explicit Content /18+, Minors DNI, SMUT… BDSM/Restraints/Bondage, custom tech ball gag, toys (Egg vibe, anal beads, dildo) Overstimulation, Toy fucking/Machine-assisted thrusting, Filthy talk (Tony can't shut up), AI assists with data tracking, clinical observation, forced openness, Sensory overload
A/N: my entry for @avengers-assemble-bingo for April Kinky Bingo… Well this one turned into a whole thing.. Square: B2- Open Up Baby Card Number: KB003
You were already strapped to the bench- back arched, thighs spread wide in glossy chrome stirrups, wrists bound snug in Stark-grade cuffs that didn’t budge an inch. The synthetic leather beneath you was cool against your skin, but your body was already starting to heat with anticipation. The bench itself shifted slightly with every movement, like it was reading your tension, calibrating every twitch of your muscles into data Tony could access later.
You could hear the soft hum of the room’s ambient systems, the low mechanical whirrs, the faint electric pulse of tech running in standby, and underneath it all, Tony’s voice. He hummed absently as he moved around you, flicking through translucent holoscreens that floated in the air, readable only to him. Light glinted off his arc reactor through the thin black shirt he wore, sleeves rolled up to his elbows, veins flexing with every subtle flick of his fingers.
He looked like a scientist. Or a surgeon. No, a goddamn artist.
“You look tense,” he murmured, stepping in close, his fingers grazing your jaw with a feather-light touch. “That won’t do. We need to get a clean read. No clenched teeth, no locked jaws. Just you- open and…relaxed.”
He held up a sleek piece of tech. A mix of leather and metal. To you it looked like a ball gag. That wasn’t just a gag. It was his gag. Something custom. Personal. Laced with Stark Industry Tech.
“Open up, baby. Gotta install the biometric reader. It’s not science without a baseline.”
You hesitated, lips twitching. Just for a second. But he didn’t push. He just waited you out, smirk deepening, one brow arched like he had all the time in the world. That cocky, knowing gaze made you squirm even before anything touched you. Your breath hitched. And then you parted your lips.
“There we go,” he said, tone thick with approval as he slid the gag into place. It clicked against your teeth, snug and firm. A soft vibration flickered across your tongue as it locked in pushing the muscle down.
Friday’s voice chimed in overhead, calm and clinical.
“Gag calibration complete. Biometric sync active. Tracking vocal response, saliva levels, and tongue pressure.”
Tony leaned down, brushing his lips across your cheek in a whisper of a kiss. “Good girl. Now let’s get to work.”
He started with the egg.
Sleek. Silver. Pulsing faintly in his hand like it had a heartbeat of its own. The metal shimmered under the clinical lights, smooth and polished, shaped with the kind of precision that only Stark could deliver. He turned it over once, twice, like he was admiring a prized gadget- one that he was particularly proud of.
He showed it to you like a doctor unveiling a revolutionary new tool- calm, confident, deeply amused. Except this wasn’t a sterile exam room, and the look in his eyes wasn’t professional. His smirk told you he already knew what kind of mess this thing would reduce you to.
"This is your warm-up," he said, voice low and playful. "Phase One. Internal warming protocol. Testing receptivity. Calibration through heat and pulse response."
You whimpered into the gag. Of course you were excited- he’d been teasing you with this little 'demonstration' all week. Whispering promises in your ear, tapping out reminders on your thigh, dropping technical jargon laced with filth that left your core throbbing before he’d even touched you. Now that it was finally happening, your whole body was buzzing with need.
He didn't wait. He moved closer, one gloved hand parting your thighs a little further, the other settling between them. The bench adjusted beneath you, lifting your hips another inch to meet his touch perfectly. His fingers dipped between your folds- testing your wetness, teasing you just enough to make your body jerk in its bonds.
"Already responsive," he muttered, half to himself, half to Friday. "She’s going to be a dream to log."
He slid the egg in with two fingers, slow and deliberate. The cool metal kissed your entrance, making you flinch slightly- it was colder than you expected, stark contrast against your heated skin. Your walls instinctively tried to resist, clenching down, but his fingers were patient, coaxing you open, parting you around the sleek, unyielding toy.
The egg slid upward, heavy and smooth. As it moved deeper, your body yielded to it, the slow stretch making your breath catch. Its contours were designed to press into every sensitive spot, and you could feel your muscles fluttering around it, trying to accommodate the sudden fullness. As he pushed it deeper, you could feel every inch of it being swallowed by your body, your slick muscles tightening, fluttering around the intrusion.
He pushed the egg up high inside you, then paused, his finger still inside you too. "Squeeze for me," he ordered. You did, instinctively, your walls closing down as you used your pelvic floor, and Tony gave the platic string attached a soft tug.
The stretch, the resistance- it was delicious. The egg stayed locked in place. You couldn’t push it out if you tried. He smiled, clearly pleased.
"Perfect. Secure fit," he murmured. "Wouldn’t want it popping out mid-test."
It settled deep inside you, a sinful throb blooming in your core. Then it pulsed- just once, a quick flutter that made you jolt.
"There we go," he breathed, watching the screen light up with new data. "Didn’t even turn it on yet and she’s already going. Fuck, I love this job."
You were barely processing the first toy when he reached for the second.
Beads. Tapered, growing in size, each one gleamed under the soft blue lighting like tiny pieces of futuristic art. You squirmed, thighs pressing together, but it was no use- Stark had seen your reaction.
Tony laughed- low and delighted.
"Didn’t know we were going there, huh?" He nudged your knees apart again, voice dipping to a darker octave. "Come on, baby. I want you to open up for me. Let’s see what this one does..."
You shook your head slightly. Whimpered into the gag. Wide eyes watching him as you tried to protest around the ball gag in your mouth.
Tony turned to the tray beside him, selecting a small, frost-blue tube of gel. "Wouldn't be very considerate to skip prep," he muttered, more to himself than to you. He uncapped the tube and squeezed a slow, deliberate line of the slick, glistening substance along the length of the beads. The gel shimmered faintly under the light, warming as it reacted with the ambient temperature.
He coated each bead carefully, fingers moving with methodical ease, making sure the entire string was evenly slicked. "Lubricated. Body-safe. Custom formula," he said with a wink. "Slippery enough to slide in smooth- sticky enough to stay in place until I say otherwise."
Then he held the beads up for you to see, the string dangling between his fingers. You tensed instinctively.
"Oh no. You’re freezing up. Can’t test properly if you don’t behave. Legs. Open."
You didn’t.
Tony tsked, clicking his tongue in mock disappointment. Then he grabbed your chin, firm and steady, tilting your head so your eyes locked with his.
"Don't think so much. That’s not what good test subjects do."
Click.
The bench tilted beneath you without warning. Your hips rolled upward, knees falling further apart as the restraints auto-adjusted. You were fully exposed now- helpless. Wide open.
"You know I can override those restraints, right? I built them. Now be a good girl and show me everything."
He dipped his finger back into the gel and brought it to your ass, pressing a cool dollop directly to your tight, puckered entrance. The sudden chill made you flinch, but it was followed by the warm glide of his fingertip as he gently teased the gel in slow circles.
"You tense here, too," he said, amused. "Don't worry. This formula warms up just like you do."
He rubbed it in carefully, working the gel into your rim with delicate, coaxing pressure. The sensation tingled- both from the temperature shift and the way his finger circled and pressed until your body finally began to relent.
Then he lowered the beads between your cheeks and began to press them in- one at a time. The first slid in easily, the gel working its magic, cool and slick. The second made your breath stutter. The third had your whole body tensing as your hole stretched just enough to accommodate the new pressure.
Each one pulled a different, desperate noise from you- somewhere between a gasp and a whimper, caught in the back of your throat and forced through the gag in broken fragments.
By the time the third bead settled inside you, you felt full. Stretched in ways that left you panting, your back arching hard off the bench. Everything was working together- the deep pressure of the egg nestled high in your core, the hum beginning to buzz through your clit like a phantom, and now the slow, firm intrusion of the beads pressing against nerves that had you seeing stars. You struggled to catch your breath, the gag forcing each inhale to be short and choppy. Air hissed through your nose while your mouth flooded with saliva, spit slipping from the corners of your lips in thick strands that slid down your neck and onto your chest. The overwhelming heat of arousal and frustration tangled in your gut, building like steam with nowhere to escape. The restraint of it made the fire inside you burn hotter.
Your muscles clenched involuntarily, your hips rocking against the air, chasing friction that didn’t come. You couldn’t speak, couldn’t beg. Just drool, tremble, and take everything he gave you.
"Mmm. That moan? That was bead three. She likes that one, Friday."
"Confirmed," the AI replied. "Pelvic floor tension rising. Heart rate increasing."
"Good. Means it’s working."
The egg began to heat. The beads hummed in sync, and you felt everything shift- internally and externally- as pleasure bled into pressure, and pressure into overload. You were trembling now, thighs twitching again, trying to close- but the bench held you wide, utterly exposed.
"Heart rate’s spiking..." Tony’s voice was pure, filthy glee. "Oh, she’s gonna break soon. Look at her squirm."
You rutted against the air, clit untouched and screaming for attention. Your walls fluttered around the egg, your ass clenching down against the beads as the different pulses overlapped and collided. It was all too much and somehow not enough. You needed more and needed it to stop, all at once.
You tried to breathe, but the gag made it impossible to take anything but shallow, panting gasps. Each exhale was laced with a moan. Drool spilled freely down your chin, dripping warm across your face and neck. You were flushed, messy, wrecked- and he hadn’t even touched your clit.
Your back arched violently off the bench, cords of heat coiling through your belly and thighs. It felt like your body was unraveling, muscles tight and desperate, nerve endings screaming with pleasure.
Tony leaned in again, voice dark and syrup-smooth. "We’ve got her plugged, egged, and ready to combust. Think she can handle the next phase?"
Friday answered, "Orgasm build-up at 87%."
"Perfect." He tapped a command into the air. "Now let’s push her."
The egg pulsed deeper. The beads vibrated sharper. You cried out- moaning, writhing, the gag muffling it into raw, incoherent noise. You couldn’t form words. Couldn’t beg. Just sob through the pressure building to a breaking point.
"Baby, this is science. Filthy, beautiful science."
It hit you like a wave- white-hot and all-consuming. Your legs shook violently in the stirrups, muscles spasming as your body locked around the egg and beads pulsing inside you. Every nerve ending fired in chaotic pleasure, overwhelming your senses. You tried to scream, to sob, but the gag reduced it to a shattered, strangled cry that vibrated through the tech, each desperate noise dutifully logged.
Drool spilled in long, wet strands down your chin as your back bowed hard off the bench, your whole body trembling under the assault of pleasure. Your cunt clenched tight around the egg, milking it involuntarily, while your ass throbbed with each hum of the vibrating beads. Everything inside you was pulsing, moving, grinding you down into submission.
Tony watched, transfixed, his gaze locked on your ruined, shaking form. “There she goes - God, I should patent that moan.”
Your eyes rolled back. You could barely breathe. You could only tremble and leak and convulse as the orgasm tore through you. The bench beneath you vibrated subtly with your body’s response.
Friday: "Orgasm confirmed."
Tony waited until you were trembling, your breathing uneven, your thighs still twitching with aftershocks that rippled through your overstimulated body. Sweat slicked your skin in a thin, glistening sheen, catching the light as your chest heaved with broken gasps around the gag. Your limbs strained weakly against the restraints.
Then- slowly, methodically- he reached between your cheeks and took hold of the first bead. He didn’t rush. He eased it out one at a time, each slick orb dragging along your inner walls with a sticky, stretching glide. You shuddered at the sensation- the unbearable emptiness that bloomed in the wake of each removal. Your ass clenched reflexively around the loss, trying to hold onto what had filled you so completely. But he kept going.
The final bead popped free with a slick, obscene sound. Your hips jolted involuntarily, your back arching once more as your body spasmed again, clinging to the ghost of sensation.
Friday's voice crackled overhead. "Anal pressure reduced. Sphincter still contracting. She’s experiencing post-orgasmic muscle spasms."
Then came the egg.
He curled his fingers inside you, tugging the retrieval loop with a firm, practiced motion. The egg slipped free, wet and shiny, your cunt fluttering uselessly around the sudden void. The stretch, the drag, the warmth- it all left you aching. You cried into the gag, overwhelmed by the emptiness and the continued tremors in your muscles. Your thighs kicked slightly, your knees drawing in as far as the restraints would allow.
"Vaginal walls contracting. Core temperature still elevated. She's not done trembling yet," Friday observed, calm as ever.
Tony held both toys in one hand now- wet, warm, shining. He looked down at you with naked satisfaction.
"That’s some damn good tech," he said. "But we’re not done."
From the tray, he lifted his final piece.
A dildo- sleek, deep grey, Stark-stamped at the base. Modeled after him, and you knew it. Maybe a little bigger. Slightly wider at the base, with delicate ridges along the underside that hinted at something extra. Your breath caught just looking at it.
“This one’s special, baby. Built it from memory- well, from yours,” Tony said, rolling it in his hand. “Temperature regulated, pressure-sensitive, and the best part? The internal sensors sync to your contractions. It responds to you. The more you clench, the deeper it drives. A perfect loop.”
You whimpered around the gag, heart fluttering.
He moved between your spread legs and lined it up against your soaked, fluttering entrance. You were already sensitive- still trembling from the last orgasm- and when the wide tip pressed in, you nearly cried. It stretched you slowly, steadily, a little more than you were used to. Your slick walls resisted at first, clenching down instinctively, but Tony was patient, guiding it with precise control.
“There you go,” he coaxed, voice smooth but sharp-edged with amusement. “That’s it. Take all of it. Come on, baby- I know you can..”
His tone dipped into a purr. “There you go. Taking it like you need it. Bet you love being filled up with Stark-grade tech, huh?”
Your back bowed off the bench as he pushed it in, inch by inch, your pussy yielding to every contour, forced to accommodate the full shape of it. The fullness was delious, your body stretched taut around it. Your eyes rolled back as the final ridge slipped inside, the toy settling deep.
“There,” he said, watching your reactions with fascination. “Fills you out just right. And now... we see what she can really do.”
The base clicked into a pulse pattern, and the toy began to move inside you- slow at first, deliberate, like it was learning your shape. You could feel every textured ridge of the shaft as it rubbed against your inner walls, dragging across oversensitive flesh, sparking little detonations of pleasure with every pass.
Then it pulsed- long and low, a rhythmic thrum that radiated from base to tip, sending heat spiraling through your belly. With every thrust, the toy seemed to stretch you deeper, nudging a spot that made your toes curl and your thighs twitch against the restraints. Your pussy clenched around it reflexively, triggering the internal sensors Tony had mentioned. And just like that, the toy responded- pressing harder, thrusting deeper, faster.
It wasn’t just fucking you- it was reading you, syncing to the wild flutter of your muscles, pulsing in tandem with your arousal.
“Look at her,” Tony murmured, grinning as he watched the toy disappear again and again between your legs. “Every little squeeze makes it work harder. You’re doing this to yourself, baby. And I haven’t even touched your clit yet.”
You’d been so consumed by the thrusting inside you, by the stretch and pulse of the toy, that you hadn’t even noticed Tony move. But suddenly, he was there- looming over you, and the egg was pressed directly to your clit.
The sensation was immediate and brutal.
Your entire body jolted. The contact felt almost painful, your nerves raw and exposed, the stimulation electric. You tried to buck away, hips arching, thighs trembling, but you had nowhere to go.
Tony caught you effortlessly. One hand shoved the egg against your swollen clit, refusing to relent, while the other pressed down on your thigh to keep your knees from closing.
“Uh uh. None of that,” he said smoothly. “You don’t get to hide from this, baby. You earned it.”
You sobbed into the gag, thrashing your hips side to side, but the bench and Tony’s hands made escape impossible. Every attempt to squirm just sent the dildo thrusting deeper inside you, and the egg grinding cruelly over your clit.
“You’re not gonna break,” he whispered, teasing. “You’re gonna burn for me.”
"Don’t you dare run from it. look at me."
He was holding you still- one hand clamped over your thigh to keep your legs spread, the other pressing the egg mercilessly to your clit. You were trembling in his grasp, utterly helpless against the merciless pairing of his tech and his control.
"You’re gonna come again for me, sweetheart. Real data’s in the repeat response," he said, eyes locked on yours, voice both commanding and hungry.
The dildo thrust deep, the ridges grinding against your most sensitive spots as your walls clamped down. The egg buzzed brutally against your swollen clit, so overstimulated you couldn’t tell whether you were trying to run from it or chase it. Every jolt of pleasure lit your nerves like lightning- white-hot and impossible to hold back.
Your body jerked, hips spasming, thighs trembling violently as the sensations overloaded you. Your entire body was working against you- every clench, every twitch, every gasp just triggered the toy to go deeper, harder, faster. You weren’t riding it anymore- it was riding you, and Tony just watched with that devilish smirk, keeping you wide open.
“That's it. Shake for me. Scream into that gag. Show me what science can do.”
The climax tore through you without mercy- harder, deeper, a violent unraveling of every nerve as your body convulsed around the relentless rhythm of the tech inside you. You didn’t just come; you shattered, splintering open in a release so intense it blurred your vision, your mind, your ability to distinguish pleasure from pain. Your vision shattered into sparks, your scream muffled into a raw, hoarse noise behind the gag. Your body thrashed in the restraints, muscles locking as the orgasm ripped through you, longer and sharper than the last.
Friday: "Second orgasm confirmed. Neural spike significant. Subject approaching physical limit."
He slowed the toy, letting it ease to a stop deep inside you before withdrawing it carefully, letting you feel every last ridge dragging along your raw, overstimulated walls. Then, with a gentleness that almost contrasted the torment he’d just put you through, he removed the egg from your clit. The instant the contact broke, your whole body sagged in the restraints with relief and exhaustion. You were shaking, barely breathing- every inch of you buzzing, nerves fried and twitching from the overload.
You could taste salt on your lips- your own tears and spit, your jaw aching from clenching around the gag. You were drenched, body glistening with sweat, your skin flushed and hypersensitive to the air.
He removed the gag last. Your jaw fell slack with a wet, trembling gasp, strands of spit clinging to the corners of your mouth. You blinked up at him, vision hazy, lips wet and parted.
Tony gazed down at you, eyes gleaming with wicked satisfaction, his mouth tugging into a crooked grin that said told you so. He looked like a man admiring his finest creation- smug, yes, but also thoroughly entertained by the glorious, twitching mess sprawled out beneath him.
“You did good, baby. Fucking beautiful. But next time?”
He leaned close, brushing a kiss to your temple- slow, deliberate, his breath warm against your damp skin.
“Think I’ll need to design something that gets you to squirt. Can’t let a variable like that go untested. Wouldn’t be very Stark of me to stop now, would it?”
He turned with a little flourish, tapping the screen with a flick of his fingers, not bothering to look back.
“Friday, save this session. Label it: Successful. Prepare files for Phase Two.”
