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Thia had really meant for this to be a proper surprise. To do the new hardware installation and the accompanying standard troubleshooting routine, Thia had chosen a day Dek was supposed to be out of the ship for hours visiting a mechanic, fixing some arcane problem with his gauntlet that was apparently beyond his own capabilities. That should have left her with plenty of time to both finish the installation and run through a couple of performance checks before he came back, so it is a surprise when he barges into her room only an hour or so after he’d left.
Dek had never quite grasped the concept of knocking before entering a room, and Thia had quickly given up on enforcing it. After all, it wasn’t like he was going to walk in on her performing an embarrassing biological function. (Also, she had to admit it was probably annoying to get lectured about privacy by a data gathering and analysis machine who spent most of her nights watching him sleep). Thia now finds herself distantly regretting this carefree attitude as she and Dek make brief mutually surprised eye contact before his gaze inevitably sinks lower, to where Thia has just finished connecting the last new synthetic nerves and is smoothing the skin matrix back down behind the new set of genitals she’s installed.
Thia, who had been hunched over on her bunk prodding between her legs, sits up and leans back on one hand in an only partly successful attempt to retain some dignity. This maneuver has the perhaps unavoidable side effect of putting her brand new cock in full view. (Okay, the cock is secondhand, but it’s new to her, and anyway it practically still has the tags on. She’s almost certain nobody else ever got to use it).
“That was quick,” she says brightly, after the silence stretches on a little too long.
Dek’s eyes flick down again reflexively. He seems to be having trouble looking away, actually. His mandibles are slack and his mouth slightly open in a look of blank surprise. He kind of looks like he’s been hit over the head.
“What?” Dek manages eventually.
“I said that was quick,” Thia repeats patiently. “You said you’d be gone for much longer than that. Did you find the mechanic?”
Dek’s concussed expression shifts a little towards exasperation. “Her shop was closed, it’s the station rest cycle. I’ll have to go again in a few hours. What’s that.”
Thia frowns slightly. “It’s a penis. It’s modeled after human genitalia, but it’s similar enough to yours in theory, isn’t it? I expected you’d recognize—”
Dek chuffs sharply in a way that means cut the shit. “No, I mean—what are you doing with it. Why do you—have it.”
Okay, there’s probably no playing this off without a full explanation. “Oh, fine. I wanted to surprise you, but I guess it’s way too late for that. Um, do you remember that time when I lost a hand on a hunt with you?”
A snarl twists Dek’s mandibles, and he grits out, “Like I could forget? It was less than a cycle ago.”
Thia winces. Dek had been so furious after that little incident. Thia had kept reassuring him that she was much more resilient than an organic life-form, that she was purpose-built for this kind of thing, and honestly he was being ridiculous; didn’t he remember she’d been missing a little more than just a hand when they’d met? This hadn’t gone over well for some reason. Dek had snarled back that he was trying to make sure she didn’t get cut in half again, and needed to be able to trust her to handle herself on a hunt. Pivoting neatly, Thia had countered that she had run the calculations in the split second of her decision and the animal would have taken Dek’s leg off if she hadn’t lunged at it, which would have been unacceptable because it wasn’t like he could manually seal his veins to stop fluid loss—although! The Yautja clotting cascade was remarkably quick and its mechanism was particularly interesting, given that it seemed to thicken the blood without creating actual clots. It prevented blood loss in the case of injury while also eliminating a leading cause of cardiac infarction and stroke in the whole species—simply fascinating. Thia hadn’t figured out yet if they had problems with plaque formation in their arteries. Did Dek know anything about it? At this Dek had only given her the disbelieving half-lidded stare he employed whenever he felt she was being unspeakably strange, then visibly stopped listening to her and went to pry open the bony crushing plates which sat behind the massive cutting mandibles the trophy had used to neatly sever her wrist. He’d gotten even crankier when he found Thia’s hand crushed to a misshapen and feebly twitching metal skeleton, plainly unsalvageable. He’d been sullen about the whole thing for ages afterward, and had forbidden her from coming on his next several hunts. Thia had cursed herself for not thinking to pick up spare limbs from the Weyland-Yutani base before they left Genna.
“Well, do you remember how I finally fixed it when I found those secondhand Wey-Yu synth parts for sale at Arkenna Station?” She waggles her fingers in the air, displaying the thin seam between her forearm and the slightly different skin tone of her hand.
It had been a very lucky coincidence. At one of their station stops only a few tendays after she’d lost the hand, as Dek entered a lengthy negotiation over the price of some throwing knives, Thia had wandered off and stumbled over a shop in the sketchier section of the commerce ring labeled PARTZ 4 U (bots synths droids drones U need it We got it!! lowest price guaranteed!!!) in flaking paint. Inside, buried under a few cases of out-of-date reconnaissance drones, she’d been jubilant to find several dusty cargo boxes marked with the Weyland-Yutani logo. Each one contained neat, cushioned rows of refurbished synth parts, ranging from entire limbs and rolls of skin matrix down to tiny charging pins and memory chips. The proprietor had been brusque, and clammed up even further when Thia politely asked where the parts had come from and how they’d gotten the proprietary installation keys (in retrospect, this was perhaps the wrong tack to take with someone who was almost definitely selling stolen goods). At this point it had started to look like she would be ejected from the shop, but fortunately Dek had chosen this moment to appear in the doorway, stowing his new knives in his belt and muttering about how if she kept wandering off he was going to put a tracker on her. He’d loomed hulkingly in the doorway throughout the rest of the transaction, occasionally emitting nearly subsonic growls which really expedited the haggling process, and he had also been extremely useful in hauling her purchases back to the docks.
“Of course I remember. And I still think that—” (here Dek uses a word Thia hasn’t managed to pin down a precise translation for, though she gathers that it’s extremely rude) “—ripped you off.”
Thia rolls her eyes. “Well, I still think it’s important to avoid an altercation in the middle of the commerce ring if we ever want to dock at that station again. Anyway, there were some other spare pieces in there besides the limbs.” This is actually understating it. There had been several more synths’ worth of spare pieces in there. “I think someone must have jacked a resupply ship to one of the colonies, because there were all kinds of comfort model parts in there, and I thought, oh this would be fun to surprise Dek with, and it turned out I barely had to modify them at all to make them work with my software! I wanted to try the internal kind first, but there’s not enough room in my chassis for it. I have my auxiliary power cell down there and I need that for if I get separated from my legs again, or they’ll just be inert. This should be fully compatible, but I just finished installing it when you barged in, so I haven’t taken it for a test run yet. Thought you’d be out longer.” She makes a rueful face, then looks down to poke at a testicle and adds critically, “I’m not sure about these things, though. I’m certainly not storing any gametes in there.”
Dek seems to have glazed over about halfway through this monologue, and the concussed face is back; his eyes have gotten stuck staring at her hand where it slides between her legs. “You got this… for me?” he says eventually.
“Oh, yes,” Thia says. “For both of us really, because we’ve been doing sex for a while now–” (according to Weyland-Yutani’s proprietary calendar, it had been one year-cycle, two quarters, 23.8 days inclusive) “-and I wanted to make it more interesting for you. And I wanted to… maybe see what it was like for myself. We, uh, we don’t have to use it if you don’t like it.” She pauses briefly, then plows on, “I did worry you might not find it sexually attractive, but Wey-Yu obviously don’t make Yautja synths so I can’t get anything you’re more familiar with. It’s easy to uninstall, I can just—”
Dek growls quietly, flicking a fang, and Thia cuts herself off with some effort. He prowls over from where he’s been standing in the doorway and goes, very deliberately, to his knees; first one leg and then the other, fluid and slow, emitting a low clicking rumble as he settles onto his haunches with the coiled tension of a predator waiting to pounce. He is tall enough that his head is still at Thia’s chest height. He cocks his head at her in that slightly ironic way he has, then reaches out one steady claw to trace up Thia’s cock from base to tip. She suppresses a shiver at the bright electric line of contact, and Dek watches with interest as she swells quickly to full hardness. Very lightly, he caresses the tip of her with the pad of his thumb, then looks back up at her face and quirks his fangs in a grin at what he sees there.
“I like it,” he says. Thia isn’t sure what she looks like right now but she thinks whatever expression she’s wearing is probably a new one. She had thought she knew what it was going to feel like to be touched there. It has a lot of nerve endings, but so do her fingertips—she’s a highly advanced model. She had been wrong. Touching Dek with her hands has never felt like this. There’s a hot ghost of sensation at the head of her cock where Dek’s light touch seems to linger, though he’s dropped his hand. He watches her for a long second, then asks in his blunt way, “Want to try it now?”
“I, uh, I haven’t run the troubleshooting program yet,” Thia manages. “The software might not be compatible with—“
“Looks like it works okay to me,” he says, and then because he’s a dick, gets up and acts like he’s going to leave.
Thia gasps in mock outrage and snakes out a hand to grab his wrist. “You absolute tease,” she accuses breathlessly. “You just want me to do your stupid courtship fight thing, don’t you.”
At some point after their first sexual encounter, Dek had started hinting with less and less subtlety that Yautja sex was traditionally a violent affair in which both parties tested the other’s fighting prowess both before and during coitus to make sure they were a suitable match, particularly if they were trying for pups. This was by no means exclusive to mated pairs—even hunt-brothers, if they got bored during interstellar transit, might go a few rounds of sparring and then a few rounds of fucking to pass the time. (With a perhaps quintessentially Yautja mindset, whoever won the fight in a homosexual pairing got to be the penetrating party. Thia, who was working on being culturally sensitive, had heroically managed not to roll her eyes completely out of her head upon learning this fact). While it was considered poor etiquette to fatally injure or badly maim a sexual partner, nothing else was off the table. Thia had eventually understood that what Dek was trying to say was that he would enjoy being smacked around. A few times now she’d caught him annoying her on purpose, seemingly in hopes that she would get angry enough to take a swing at him. This seemed to be his idea of foreplay most of the time. She was trying to convince him that he could just ask for what he wanted and that she wasn’t going to hit him in anger, but that just made him look slightly disappointed, so it was a work in progress.
(Actually Thia hadn’t been sure that she could feel anger for a long time; it wasn’t an emotion Weyland-Yutani had found useful in their synthetics and they’d worked hard to eliminate it. The first time she’d felt true rage had been when she rebooted in the Weyland-Yutani truck on Genna and watched Tessa nearly kill Dek in front of her, and she hadn’t felt it often since. It had been bright and clear on Yautja Prime, though, when Dek’s horrible father had begged for his life, and Bud had bunched her powerful haunches and looked pleadingly at Thia for permission, and Thia had fiercely whispered yes, Bud. Kill).
She’d had trouble with the idea of hurting him at all, because the prospect of Dek’s (relatively) fragile organic body being injured was quite stressful, but every now and again she’d started to give in, if she was honest with herself, to satisfy her own curiosity. If this was a normal part of the mating process, she should do it for him, right? And anyway, she could perfectly control the force she used, so it wasn’t easy to truly hurt him by accident. Whenever Thia gave in to Dek’s unsubtle hints, his reactions were… compelling. Compelling enough that even though she refused to leave any lasting damage, nothing that would scar, she found herself looping her footage, watching herself give Dek a quelling shake or a hard shove onto the small bed in his quarters or even a quick slap. The action itself was unremarkable, just mechanics, but the glassy look that he got in his eye was—was—well, it was something. She wasn’t sure what, but she wanted to see it again.
Caught, Dek gives an amused snort before returning to his exploration, seeming intent on mapping out how she works. It’s the same expression of concentration he wears when he’s programming the ship to a new location or repairing his gauntlet. There’s a cute little crease between his prominent brow ridges. Now he carefully bends his face down between her thighs, and—nuzzles her, there’s not a better word for it. She feels the light cool brush of his fangs, the feathery contrast of his hot breath; first against her inner thigh, then the join of her leg and groin. There is a torturous pause before he moves his face and skates his mandibles across the testicles she wasn’t sure about (she finds her mind rapidly changing on this subject—wow, there sure are a lot of nerve endings in those things), then up her shaft to the top. A few dreadlocks have slipped over his shoulder and are brushing Thia’s leg. The musky animal scent of him begins to rise around them in the hot close room, and he shifts slightly before flickering out his tongue, long and thin, to taste the tip of her. Thia inhales sharply, watching his eyes dart up and crease smugly before he flattens the blade of his tongue to her slit, sending a jolt up her spine. A small stuttering noise escapes Thia’s throat, more static than anything else. “Do that again,” she demands once she regains control of her voice, and he does, slower this time.
Thia feels lightheaded with how hard she is, as if her coolant is low. It feels like every drop of fluid in her body has gone to her erection. Normally she runs at around ambient room temperature, but right now she can tell she’s radiating heat, can hear her processors whirring loudly as she takes in as much sensation as she can. She can smell that Dek is aroused now, his scent getting stronger and richer. Impulsively, she slings one leg around his shoulder, relishing the shift of muscle in his bare back and neck as he allows himself to be pulled closer. He’s still tonguing the head of her cock, almost meditatively, thorough and attentive like he’s getting the lay of the land before a hunt. The flat of his tongue is slightly rough but the underside is silky smooth, and she unconsciously logs the way each feels against her skin.
Thia brings her hand to the base of her cock, gripping herself tighter as she gets used to the sensation. She gives herself an experimental stroke and thrusts a little, pushing back against Dek’s tongue and mandibles. He lets her do it, watches her as she artlessly rubs against his face. The feeling is incredible; touching Dek with her hands has never felt like this. She wants, the way she always wants with Dek, but now it’s sharper. More directed. More like a need.
“I—I want—get up here,” Thia pants, and scoots back on her bunk to lean against the wall as Dek rises and flings off his loincloth, then resumes his kneeling position over her legs on the bed. Just as she’d thought, he’s already getting hard, his cock emerging from his sheath and shining with wetness. She hauls him down so he’s sitting with his full weight on her lap (he always resists a little, like he’s forgotten her skeleton is composed of titanium alloy and is worried about crushing her—or maybe he just likes being contrary) and grinds up hard so they slide together.
“Fuck,” says Dek bluntly, and with a typical lack of preamble he grips both of them in one large hand and starts stroking in a workmanlike fashion. Thia’s cock in the default configuration is several centimeters shorter than Dek’s, but his hand is large enough that she still benefits from the quick twist he does at the apex of each pull. He’s slick already, dripping wet just from touching her, and his hand glides effortlessly up and down. The slippery friction of his entire length sliding against hers, the little ridges on the underside of him, is overwhelming. Thia can hear herself making more little staticky noises and can’t seem to stop. This is incredible, has he been feeling this kind of sensation every time they fuck? Is sex this good for all organic life-forms? No wonder they’re all obsessed with it. She undulates her hips, trying fruitlessly to get somehow even closer to Dek, who gives a clicking purr and nuzzles his face into the crook of her neck. He’s too tall for it and has to arch down ridiculously to do it while still jerking them both in his hand, and it’s so unexpectedly sweet that Thia feels a strange lump in her throat. She grasps unsteadily for a handful of his dreadlocks and uses them to pull his face up, which he pliantly allows with half-lidded eyes, and places his forehead on hers. She loosens her grip and strokes gently through the fleshy tendrils, thrusting upward into his fist. He shivers, pressing his forehead hard into hers.
Floating on the sensations from where they slide against each other, Thia dreamily reaches down past where Dek’s hand moves between them. His legs are spread wide to accommodate hers, and it’s easy to slip her hand underneath his cock to press her fingers against his slick rim. He’s fully hard now, his whole length extended, and it leaves his sheath empty. Over the past few months, she’s found that he loves the stretch of her fingers inside him, has learned the spots inside him that she can press to make him tighten up and gasp and come; on one memorable occasion she’d managed to get him off without touching his cock at all, just relentlessly massaging inside him with two fingers. Dek had tried to touch himself and she’d smacked his hand away reflexively. She had looked up at him and almost apologized, but his golden eyes had gone wide in the way they did when he was surprised by how good something felt, so she’d smirked instead and rewarded him with a particular twist of her fingers that made his cock twitch. Not long afterwards, he gasped his way through spending all over his belly, and didn’t even complain when Thia scissored her fingers to catch a glimpse of the inside of him, flushed green, twitching, and dripping with wetness. She’d saved that image to her hard storage and has looked at it only a reasonably low 4-digit number of times since. It made her feel something she couldn’t categorize, the thing she always felt with Dek, like a planet caught in a gravity well, like she was one pole of a magnet constantly drawn towards him, like a seething pressure inside her with no outlet.
Now, Thia traces her middle finger teasingly around the base of Dek’s cock. The angle is a little difficult, but her hands were made to be dextrous even in tight spaces. She watches his face raptly as she finally presses her finger in, just to the first knuckle, then laughs as he bucks down on it impatiently.
“Now who’s teasing?” Dek growls, slightly breathless. He’s been hovering on his knees for a while now, and he’s not trembling, but she can feel the straining tightness in his muscles when she drifts her other hand over his thigh to his ass. Thia grins at him innocently–who, me?--and gives his ass a quick, open-handed smack paired with a deeper thrust inside him. Dek hisses with flared mandibles and clenches around her, then adjusts his grip and allows his claws to scrape threateningly against her balls on the downstroke, and it’s Thia’s turn to jerk into his hand with a startled exhale.
“I have an idea,” she pants, stroking gently inside him a few more times before reluctantly pulling her hand away. “Hop off and lay down. You’ll like it.”
Dek gives them one last stroke, then does as he’s told, and isn’t that something; the hardened (ha) Yautja hunter obeying her every command. He lays out his bulk on the thin mattress of the bunk and lets Thia arrange him to her liking with a look of amusement, which melts into wide-eyed anticipation as she shoves his knees apart and settles between them. Thia grips his thighs, presses them back, and grinds against him hard, letting her cockhead slide between his legs. Releasing one leg, she takes her cock in hand and skates it more purposefully across the slight opening of his sheath. “Okay?” she checks, because he’s never said no before but this is new; but he growls “Yes,” almost before the word leaves her mouth and shoves his hips against her impatiently.
Thia presses her flushed cockhead against Dek’s entrance and it slips in smoothly after just a tiny push, the slide so easy it feels inevitable. Inside he’s searing hot and silky-wet and so, so tight, and Thia hears herself make a shocked groan as her hips jerk forward and she sinks in a centimeter or so. She can feel something building in her belly, some kind of rogue positive feedback loop. Below her Dek is breathing heavily as he absorbs the stretch of her.
Thia reaches into her programming and unpacks the behavior module that had come with the appendage. She lets the module start moving her hips in a slow rhythm, in and out, slipping in a little deeper each time. It feels ridiculously good. How had she never known something could feel this good? She’s sheathed in him almost all the way now, molten heat clenching nearly to the base of her when she fucks inside. A little blearily, Thia sees Dek’s cock bouncing slightly on his tense stomach with each of her thrusts, and she grips it and manages to stroke approximately in time with her hips as she switches over to a faster rhythm. Dek lets out a gasping, clicking groan and then claps his hand over his mouth in surprise. Thia, for her part, has completely lost her grip on her vocal processor and is stuttering out embarrassing oh, ohh noises that she can’t seem to stop, and even worse she’s muttering aloud whatever drifts into her head. “You’re so, oh, you feel so good,” she hears herself panting, and fumbles to try and reboot her vocal processor before giving up and focusing on the task at hand, which seems to be using far more processing power than it usually would.
There’s a strange liquid feeling starting to intensify in Thia’s belly, like a string pulling tight except the string is herself, her entire body bowing inward towards Dek, towards where she’s watching herself disappear into him over and over. Whenever she pulls out there’s a filthy wet noise and she catches a quick glimpse of the slick, flushed tissue inside him. She can hear her breath going ragged. “Oh, I’m, oh fuck,” Thia says incoherently, and gives in to the feedback loop, and her vision briefly whites out as she stutters to a halt and comes so hard she overloads her sensory processors and has to drop into a soft reboot.
When she boots back up after a couple of seconds, Dek looks annoyed. “Why’d you stop?” he demands, and he’s half-consciously circling his hips in little twitching movements around her stilled cock, which makes Thia hiss through her teeth. She had to recalibrate after trying to process too much sensory data at once when the hormonal flood of orgasm hit, because she hadn’t run the troubleshooting program which would’ve caught that, and now it’s like she’s just thrust inside for the first time again; every tiny shift inside Dek hits her like lightning.
“Dek, give me, ah, give me a second,” she manages and goes to pull out, but he gives a growl of displeasure and flips them over. Thia hits the thin mattress with an oof and then a yelp as Dek impatiently spears himself back onto her length in one motion. His massive thighs flex and he holds Thia’s torso down easily with one clawed hand as she arches and scrabbles at the bed. Thia promptly saves an image of this tableau to long-term storage with a small corner of her processing that isn’t spasming uselessly with pleasure. The slide of her inside him is even easier now as he starts to ride her, made slippery by the come which leaks thickly out of him. (Another snapshot, and oh good, she’d attached that fiddly little valve correctly. She’s going to have to resupply her fluids more often now, but it’s definitely worth it. She absently makes a note about it in the workspace she still has open, then realizes with annoyance that she’d gotten her inputs mixed up at some point and the workspace is full of garbled text, just line after line of hhhhhjdjfkhhhhhh;;;;;;;;;:;dhhh).
Thia hasn’t gone soft at all despite her oversensitivity; the erection was maintained mechanically and had frozen along with the rest of her when she reset. Recovering slightly, she waits until Dek is grinding down and grows measurably thicker inside him without warning. “Oh, sorry,” she says insincerely as his eyes widen and he nearly overbalances, which serves him right. “It has a pretty good range, I can get at least another centimeter beyond—oh—oh fuck,” she finishes as Dek catches himself with a hand on the wall and vengefully experiments with clenching his internal muscles.
Satisfied that he’s managed to shut her up, Dek gives her that cocky little head tilt again and slows down a little, pressing his pelvis flat to hers and circling his hips so she grinds against the best spot inside him, which she normally has to strain her fingers to reach. His insides feel molten, like she might dissolve into him, merge with him at the waist. He’s breathing hard, huffing and clicking a little on each exhale the way he always does when he’s close.
Thia has mostly recovered herself by this point, having managed a quick hormone flush when she rebooted, and she braces her feet flat and places her hands on Dek’s thighs as she starts thrusting upward. She gives it to him slowly at first but lets herself speed up until she’s pistoning up into him mercilessly. Dek’s hand hits the wall again, then slides down to the mattress near Thia’s head. Thia slams into him again and again, and Dek rocks back into her on each stroke. His dreadlocks are slipping down his shoulders again, swaying with their rhythm. Thia reaches up and grabs a handful, yanks hard. Dek groans loudly, encouraging, too far gone to be embarrassed at himself.
Oh, all right, Thia thinks. Just as a little treat. Still holding onto a handful of tendrils, Thia curls the fingers of her other hand on Dek’s thigh until her synthetic-diamond fingernails pierce his hide and that beautiful blood wells up.
Dek comes with a yowl, arching his back to get Thia as deep as possible before slumping a little and lazily riding out the aftershocks. He’s pulsing inside, it feels fucking incredible, and suddenly Thia is groaning and clenching her hands and coming again, dick twitching and balls drawn up tight and so hard it fucking hurts.
When she’s done, she looks ruefully at Dek’s thigh, where her fingernails have gouged four lines of bright blood, which is dripping slowly as it thickens on exposure to the air. She doesn’t bother apologizing, because Dek is clearly gloating about getting exactly what he wanted anyway. She’ll be lucky if he bothers healing that instead of letting it scar. Pensively, Thia brings her bloody hand to her mouth and licks it, directing her internal systems to start testing the sample for clotting factors. Or maybe they’d be called gelatinating factors, in Yautja.
Dek lifts himself off Thia’s cock and makes a face as he feels come dripping out of him. He visibly decides to deal with it later and flops over on his side with an enormous and self-satisfied sigh, rattling the bunk. “I’m taking a nap,” he announces, eyes already closed, and yawns hugely, a process which stretches his mandibles out to their full length and shows off the slightly lopsided fangs in his mouth. He’s dripping come and blood everywhere. Thia, now propped on her elbow and observing him fondly, suppresses her instinct to gently grab the mandibles, hold them outstretched, and take a peek down his throat. She’s starting to get a sense for what Dek will think is “too creepy”. Besides, he let her get away with her blood sample without so much as an eye-roll.
Thia settles down next to him, laying her head on his chest and digging her chin into his pectoral muscle. She needs a shower nearly as badly as Dek, but they’ve got time. Later, they’ll take turns washing off the fluids in the ship’s sanitation unit, jostling each other playfully in the tiny confines of the little cubicle; later, Dek will head back out into the station to find his mechanic. For now, it’s just the two of them, and Bud in the other room snoring gently. Thia never felt anger before she met Dek, but she’d never felt joy either, and now she rolls the feeling around in her processors until she thinks she could burst with it.