Author's Note: This is smut and assumes you're over 18 in reading it.
Tags: XCOM 2, female Viper x female human, cuddling, breathplay

The news is abuzz with coverage on gene therapy for civilians and ADVENT troops alike. Genome check-up and immunization against potential pathogens that were dormant for so long, that they've become viable terror weapons. Me and my girlfriend are still awaiting our call for therapy. This shit's frankly quite terrifying.

I lean back against my Viper's coils and taut stomach, reaching down towards her scaled hand scratching along my thigh. She's nervous. I can guess why. Stheno's second-gen, no need for some of the genetic modifications her earlier generation had been given on the whole initial peacekeeping and pacification before our Benefactors had committed to global Unification. She and a whole generation of Vipers were essentially skipped on filtration lungs, or a changed trachea. Now that the XCOM threat is actually real, however, more and more soldiers are getting called up for what's essentially upgrades for field deployment.

The serpentine woman behind me tenses, slowly squeezing my leg, her left hand resting over my chest. Her fingers curl and twist before my breast, her expression furrowing into a frown. I look up and back into her ruby eyes, reaching back up to caress her slender jawline. "Something on your mind?" I ask my gorgeous snek.

My eyes draw down towards her hands, and I press back against her chest closely. Her hand across my chest swivels and flattens the fingers horizontally. She lightly prods me just away from my armpits, right to left, then again, left to right, and indicates a ribbon with her hands, untwining it between her fingers. Her hands rise up ahead of me, palms aimed towards me, her dark fingers slipping towards my face and hers. Her hands lower again, and the right hand makes a leaping motion over her left hand. Then again the prods just shy of my armpits.
>I'm just worried about the genetic therapy.

I smile, looking back at the Viper. "Never been one for needles?" I tease. She shakes her head, signing it's nothing of the sort.
>I fear the changes.

I slowly push her hands away from my chest, sitting up in her coils until I can shimmy my way around to face her. My pert butt rests back against the muscular sides of her lower body, my feet pushing lightly into the thick tail. My hands take over for my voice, but I speak all the same. I can see how her face is a little scrunched up, how her hood is next to flat against her neck. She's definitely worried. "The Benefactors wouldn't just call up everyone for gene therapy if it wasn't serious."

Stheno shakes her head again. Her hands motion in the negatory, her hands rising in front of her chest and face and covering them as if shielding, her fingers nearly clasping into each other.
>That's not my worry, either.

I frown, my lips falling in an exaggerated expression of frustration. My hands make sweeping motions ahead of her and myself. My hands curl up and turn over one another a few times. "What do you fear about the changes then?" I ask in tune to my hands' motions.

She motions with her right hand, closing and opening her hand with her index and middle finger aimed upwards, the thumb held downwards, like a talking mouth. She motions to herself and then to me, then points up to her mouth, making dismissive waves down across her chest and then outwards to her own armpits. Left, right. Ribbon unfurling. She sighs almost theatrically, a rasp leaving her throat. Stheno's fingers pinch together, as if to hold something thin in front of her, and then holds her right thumb up to her chin, her face scrunching up something awful.
>I may be getting all kinds of additions. Like a throat like the Thin Men were given.

I cant my head. I don't follow.

>Our predecessors. They are unlike how you know my kind.
Stheno pauses, struggling for the words. She tries to get back to explain Thin Men, but she stops halfway before she's made a sentence. She instead says something else, motioning to correct herself.
>I get to speak. I may look different at the end of treatment. What then?

I lightly press my hand to her throat, stroking along the thick ventral scales of her neck and towards her jaw. My lips lightly press to her warm throat, pulling back after a soft smooch.

"You do what you have to, babe. You'll keep us safe. But you're still you. I trust you. My Stheno." My face flushes a little, my lips curling into a smile. "To be honest, it would be easier for you to be able to speak anyway."

Stheno gives an annoyed hiss. She holds her hands up, palms upwards, and motions her hands to each other a few times. Her right hand forms a fist and bats into her left palm, then she motions out from her mouth and grabs the breath from her lips to motion fluidly towards me.
>How can you be so candid about this? You don't worry about me changing? I worry about how you see me. What you fell in love with, -

I cut her off. I notice she motions the same words that I do, but her hands fall to my lap as I speak them and sign them. "WHO I fell in love with, Stheno. Not what." I pause. "Well, it does help that you're a giant serpent for me to cuddle up to. But I fell in love with you. The big girl dancing to jumpstyle. The soldier. The most selfless woman I have ever been with in my life so far." My body slumps against her broad chest and muscular stomach, stroking down along her scales. "You could be human for all I care. Or a Muton."

Stheno gives a sibbilant laugh, a stutter and a hiss that soon ends in a low rasping rattle from her throat. She waits until she can sign in front of my face. It's a long while. I love holding her. I love rubbing my face into her scales. She smells faintly of sand. The beach.

>Mutons aren't the cuddliest.

"You would be."

I kiss her breast, nuzzling into the scales, feeling how the firm teat smooshes against my cheek. "I wonder if that gene therapy would work for humans like it would for Vipers. I could be a slender hooded Viper just like you. With thick coils to wrap around your own. And the most gorgeous hood and pointed face."

Stheno laughs again, pushing me away. She tries to sign, but I'm too much in the mood to push up against her. My arms wrap around her chest, under her own arms, my lips brushing over the smooth scales of her left breast until I can work my way up towards her throat. "And a beautiful thick tongue to caress you wiiith-" My words trail off, my small red tongue teasingly drawing over the curve of her neck along her throat. Stheno squirms beneath me. She could easily take charge. Overpower me. She often has. But the moment I feel she isn't, I slowly bring my hands up to grab hers, and push down against my lover. I press my teeth into her scales, scraping them over her smooth armoured skin.

"I could be as big as you. As long as you. I could use my tail like you so often have." My fingers squeeze her hands tightly as I hold her in place, and my face lowers towards her snout. I teasingly lick her rounded point of her face until I can slowly slip my tongue against the hard scales of her upper lip. "I could feel you choke around my tongue…"

My legs wrap around her lower body, and I start to grind my jeans against her hard scales below her stomach. She pushes back into my body, her muscles going taut against my own tummy, her nethers pressing into my spread thighs. I push down harder against her body and work my way towards her mouth again as she slowly parts her jaws. How often have I not looked up into her mouth, before she thrust into my throat and had me blacking out from the kiss? I'd love to repay the favour.

I suck down on her throat, and slowly relinquish my grip on her hands. Instead, my hands move down under my chin, until I push with my thumbs against her trachea. "I want to do what you do to me," I whisper heatedly down to my snek. She breathes deep. Her body contracts closer in on itself. Her eyes lid. And then she nods.

I squeeze down on her throat with the full weight of my upper body on her neck and throat. A surprised cough leaves my serpent, and she grips my shoulder and upper arm tightly in her hands. She isn't struggling, however. She squeezes tight on me, and I squeeze harder on her. I kiss her snout, I lick her opening mouth until I can see her black and purple tongue eke out of her maw. I kiss it, I kiss her pink insides, I kiss her scaled lips. I push down harder on her and can feel the large Viper's body gripping around my lower body.

Stheno's body grinds closer into me. I can feel heat, moisture, softness. Sometime in our struggle, her aroused cloaca has begun to spill past her scales. I grind down with my body into her. My sole focus is my Stheno, her pleasure. Her chest heaves, her upper body wincing and turning as she feels the need to breathe so heavily. She's bucking, as if in a panic, her body rocking into my thighs. I push down, kissing her nose, her snout, her chin. Her grip on my arms grows slack. I don't let go. I force my kiss into her mouth again, tasting her tongue. How often haven't I choked on her? This is a treat for her. I savour it. I grind back down into her just as hard.

I count down when I feel her grip on my lower body slack as well. Only after a full minute do I let go, and close her mouth firmly with my two hands. I hold tight, and press my lips to her nostrils. I breathe into her, deeply.

Stheno comes to at last after me breathing a fifth time into her nose, gasping, choking, and then sputtering a cough. I pull back. I had almost considered heart massage. Would that even be the same for a Viper as for human beings? Then at last, she reaches up for my face, stroking my own jawline. She gives a sputtering hiss of a laugh. I lean back, pushing my weight down on the puffy, moist flesh of her womanhood absolutely soaking my own pants through and through.

I sign to her. Numbers in letters. She signs numbers on one hand back. She's fine. Thank goodness.

The Viper slowly signs down across her breasts and belly towards me, her eyes looking a little loopy and lazy.
>You'd make a wonderful Viper. But I fell in love with the best human.

I push down on her lower body, grinding slowly down against her cloaca. "I'll never change, pretty snek."

Stheno surprises me when her voice rasps and she gives a throaty approximation to 'gud.'

"I might learn to love your voice, though, baby."

Stheno smacks my hands away from her chest and gives another hiss that's close to her laugh. I lean back down on her, and firmly kiss my woman, my tongue probing the serpent's own. My limbs lock around her muscular body. I don't let go. I never will let her go.