I don't bother checking where the dial is. As soon as the machine is in my arms I yank on the control knob.
"The dog goes, 'Woof, woof'"
Good. Nice and simple. Now Kristie can take me doggy-style as a doggie. But something is wrong. I didn't feel the puncture this time. Did I already break this amazing device? I look at my hand to see if it's bleeding like last time. I carefully set the See and Say aside and sit up. I stare at my palm willing it to bleed and show me that it is working its magic.
The blood never comes, but I do see what looks like a small black bug crawling around my palm. Except wherever it goes it multiplies. I scratch at it and it feels soft to the touch. Under my fingers, it moves back and forth and as it spreads I can finally tell that it isn't a bug, I'm growing black fur. The fur expands, rippling across my skin and unfolding beautiful soft hairs over every inch of my naked skin.
Unlike the duck feathers, the fur coats my whole body. I watch it fill in and find shades of different colors as my head whips around trying to follow the cascade of changes. The black is so dark it looks almost purple, but over my breasts, the back of my thighs and my feet, the fur softens to a creamy tan color.
I recognize the distinctive Doberman coloring my body is assuming, but I can't get over how gorgeous I it looks. Kristie seems to agree since she starts stroking my belly with a look of delight on her face. I smile back at her, but I feel my tongue thicken and fall out of my mouth. I watch it pulse and grow. It extends down over my chin and hangs off into space.
Next my mouth follows after it. I cross my eyes and watch as my nose flattens and stretches out of my face. The extended facial bones eventually recover my wayward tongue. I soon have a fully formed muzzle to go with my new longer tongue. I stick it back out between sharper teeth than I remember. With my muzzle, I now have far greater leverage to control the extended muscle.
I feel a familiar tickle start up above my ass. I turn to see a short bony protrusion break through my skin and quickly wrap itself in muscle and fur. I wag my stubby tail and giggle at the giddy feeling it gives me.
My fingers thicken and I can feel great, stronger even. I can also smell the remains of our ducky lovemaking. The scent of sweat, sperm, and vaginal fluids fills the air. Additional scents waft up from Kristie. Without even looking I know she's eager for more. Her pussy reeks of sex and it's making me hornier by the second.
I can't wait for the final change. I crawl over to Kristie's crotch to try out my updated assets. I grab her thighs firmly in my furry hands and ram my muzzle into her dripping pussy. Kristie coos and starts scratching my back. My nose snuffles along her skin until I find the source of her aroused scent. Before I can even think about it, my tongue flies out and licks around her lips so fast it laps up all of her lubrication in a hot second.
"Oooooh," she moans. "Please do that again baby. That felt so damn good."
She doesn't have to ask me twice. Running on instinct, I lick her shaved vagina over and over coating her with my saliva. Her body arches and curls in reaction. Moans spill from her lips and urge me further faster until my tongue is just a blur assaulting her flesh. I'm amazed at how much I feel beneath my tongue. My taste buds are alive with the delectable nectar of my girlfriend.
But it's more than that. Each swipe guides me between the petals of her vagina and I can feel the silky smooth texture of her skin hug my tongue. Her labia caresses me with every stroke. It hugs my organ and begs me to enter.
I can feel her clitoris growing with my attention. It started out as a small nub with my first lick. But every subsequent tonguing brings blood to her bundle of nerves. The protective folds part under my tongue and she grows. My sensitive tongue can feel the minute variations in size as her clit engorges on her lust.
Her body quakes under my tender touch. Aiming for her love bud becomes increasingly difficult. I straddle her chest to take control. And I can feel the cramps begin that signify the final transformation. Kristie squirms and bucks underneath me. Her hands lash out trying to grip anything she can. They dig into my fur making me growl with pure lust. And she screams out herself.
"I need you inside me. Now!"
My own pussy feels like something is slowly filling it up. The change is completely different from the last one, but I have more important things on my mind. With one rough thrust I plunge my tongue into Kristie's crevice. The sides of her channel undulate around my probing tongue. My taste buds are saturated with her fluids and burn with joy.
She grabs my tail and hugs my body tightly to her. Her hips reflexively hump into my muzzle. But unlike a real dog, I still have humanoid fingers. I separate my torso from her belly just enough to slip one hand between us. While wriggling my tongue inside her, I put my finger to her button. As soon as I touch her she explodes.
My fingers race across her clit urging her orgasm to propagate with every single touch. Her vagina clamps down on my tongue and pulls it still deeper into her hole. She mashes her face against my crotch and I wonder if she's going to return the favor despite her raging orgasm. I feel something easing into the space between our bodies and hope she doesn't distract me too much before I finish with her.
Kristie devolves to nonsensical gurgles and frantic scratching. Her pussy gradually calms down around my tongue and I suck it back into my muzzle. I slide off of her and feel a stinging in my crotch. Looking down I am stricken mute. I don't know what I expected, but seeing two hanging balls and a thick red cock was definitely not it.
Somewhere in the back of my head I remember that Kristie said something about the device having male and female settings. And she was the last one to use it to be a mallard. I reach down in a daze to touch my additional parts. My cock feels slick and is pushing out of a furry flap of skin just above my balls. Simply touching it makes my guts twinge with desire.
Turning to my friend I see that she is already three steps ahead as usual. She had crawled up to all fours and didn't even bother with transforming herself. All I can see is her heart-shaped ass wiggling at me.
Her voice drifts back over her prone body. "Take me, Angel. I need your thick dog cock."
I growl in response and quickly kneel behind her. I grab her hips and guide my dick to her wet hole.
"Don't worry darling. I'm going to give you more than you could ever need."
My voice comes out deeper than normal, but I have no time to worry about that. I'm amazed at how sensitive my cock is. I barely ease the tip into her lips and the warmth surges through me. Without hesitation I plunge into her waiting crevice. Half-way through my progress hitches, but my grip tightens and I slam through until my freshly formed balls slap her pink flesh. Looking down I see a dribble of blood leak out around my member.
Terrified that I might have hurt her somehow, I withdraw and ask, "Are you okay?"
"Oh God yes. Don't you dare stop."
The splotch of blood is bright against the blanched and veiny look of my now fully erect dick. But she says she's fine and with the tip still wrapped in her warmth I'm not sure I could stop if I wanted to. I let loose a growl from my muzzle and pound into her ass. I fill her pussy with my meat. My crotch slams into her body so hard her moans vibrate out through her throat.
Her slick tunnel sucks me in and suckles me. The heat of her body spreads out through me and absorbs my mind. My hips move faster in time with my speeding heart. Her hips buck into me eagerly swallowing everything I can give her. A new sensation burns through me. I can feel her pussy tighten on my dick. At first I think it is Kristie's orgasm, but the tightness is only near the base of my rod.
Soon I can see the difference. Every time I pull out for another thrust I can tell my cock is growing. After a few more ball smacking hits I can no longer pull out. Her lips bulge around my inflation and she squeals like a stuck pig. I hesitate briefly, but Kristie allays my fears.
"Dear gods that is amazing," she screams. "Fuck me harder! Fill me with your seed!"
"Just try and stop me darling."
I'm more than happy to oblige. I'm not sure how well I can work with my cock trapped within her, but I'm eager to find out. My hands tighten on her hips and I draw her hard into my belly. Without delay, I slam into her as best I can. I find it even easier while tied to spear into her writhing body. I no longer worry about pulling out too far or pushing too hard. My sole concern is filling her hard, fast and repeatedly. And I find my upgraded body has power and endurance to spare.
My hips buck into her thighs with machine gun speed. My cock swirls within her crevice widening her walls and setting off her orgasm. Her pussy draws on my dick like a starving newborn and I can feel the bulge moving deeper into her burning hole. The grasping pussy and blazing heat sneaks into my balls like a seductress. They speak the language of hormones and seek to coax them to empty their wares into her. It is by no means a hard sell.
The tingles start low pulling at my testicles. I can tell I'm going to cum and give her one last thrust before my balls release. My semen flows out like a hose and the sensation of it surging through my organ is indescribable. My body bursts with joy and I collapse onto Kristie's back.
I suddenly understand why men so often act exhausted after sex. My body aches in all the right places and I'm glad that I have a few moments to collect myself before the bulge deflates enough to free me. I slip my cock out of her and stagger off to the couch. Taking a deep breath I admire Kristie's beautiful ass and her still twitching vagina pointing up at the world. I close my eyes and wait for the change to happen.
"Oh no you don't. I've been waiting to take a knot like that for too long. And I'm not giving it up after just one go."
I look down to see Kristie's eyes glittering between my legs. She's obviously up for more, but I can already feel my skin tingling in preparation for the shift. Before I can utter a word, Kristie lunges forward and sucks my hanging testicles into her mouth. The wet heat of her mouth brings lust roaring up to displace my lethargy.
The tingling stops immediately and the tip of my hidden cock starts to inch out of my sheath. Her hands reach between my body and the cushions and scratch my back. My legs wrap around her body pulling her close. Her tongue bounces and plays with my balls. Her expert licking makes my cock emerge rapidly from my sheath. The glistening red rocket starts to pale as it gorges on blood.
My eyes squeeze shut as I fight against the warmth of her mouth to regain control. Suddenly it's gone. I open my eyes in time to see Kristie straddle my legs. She grabs my face and kisses my muzzle. Her tongue eases between my teeth and I can taste my balls on her breath. I return the favor slipping my tongue between her human lips. It's bigger and longer than I am used to and my muzzle opens wide allowing my organ to slide deep into her throat.
She takes a deep breath sucking my tongue in as if it is a cock. Her throat embraces my twisting tongue and drives me wild. After a moment I realize I'm unconsciously humping my erect cock against her belly. It slides against her smooth flesh and sends shivers up my spine. But Kristie breaks contact gasping for breath. I take advantage of the space between us to try out my tongue on her bare nipples.
Soon her heavy breathing takes a lustful tone. I coat her breasts in saliva drawing my rough tongue across her breasts. It pulls at the underside of her breasts and travels every inch of her flesh. Her hands dig hard against my back urging me onward. Her hips grind against my sheath rubbing her clit against the soft texture of my fur.
Then her hands rise up behind me and grip the back of the couch. She pushes herself up along my torso until my dick eases against her opening. She kisses my forehead and gently lowers herself onto my rigid member. Her pace is excruciatingly slow. I feel every movement as her lips part before the beveled tip of my penis. She pauses after every incremental drop to apply a kiss to my face.
Her nectar drips lazily down my shaft. I find myself growling deep in my throat. I am on the verge of begging her to continue when my body takes matters into its own hands. My back arches desperate to plunge my meat into her waiting pussy. But Kristie anticipates my movement. She shoots up and off my pole. Her eyes take on a teasing light and she shifts her ankles over my thighs pinning me to the couch.
Her meaning is clear. This is her show and she's the one in control. She maneuvers herself onto my rod once more, but this time she takes twice as long sliding my cock into herself. Every touch of her silken flesh is at once heaven and torture. Her heat radiates through me beckoning me inside, but her rock-solid control does not oblige. It seems like an eternity before she reaches the few inches of penetration she previously abandoned due to my impetuousness.
Every ripple and contraction of her flesh sends quivers to my gonads. They scream at me to plow into her like a farmer working his field. But I rein in my desires. I focus on the pleasure and letting her do whatever she wants. By the time I hit bottom I'm so worked up I'm kissing, licking, and nipping every inch of her skin I can reach. And it's still not enough for her.
Her hips move in slow circles. I feel the tip of my organ rubbing hard against the deepest reaches of her cave. My breath escapes in ragged groans. The sensation of my knob grinding against her tender flesh is incomparable. But it is soon replaced with a tight squeezing sensation. It feels as if her cunt is gripping the tip even tighter, but the tension moves slowly down my shaft.
The pressure against my tip disappears, but I can feel Kristie sink gradually in my arms. She hisses out a deep breath between her teeth. She breathes slowly and carefully as if she's managing pain more than enjoying teasing me and working my shaft inside her. It isn't until her buttocks land on my legs that I realize what happened.
The force of gravity and Kristie's patience achieved what my previous forceful pounding couldn't. My cock has breached her cervix and allowed several inches of me into her womb. My sheath is also pulled into her pussy those few inches matting my hair further with our fluids. Her hips continue to circle gently widening her opening. And after several rotations she comes alive as if she grabbed a live wire.
She bucks against my body impaling herself on my cock. She bounces like a child on a trampoline and every time she lands she takes my whole length and then some. It isn't long before I feel my knot growing once more. But it doesn't even slow her down. She moans appreciatively when it first starts to rub against her lips, but she maintains her movements.
Eventually it grows too large to leave her and she replaces her high hops with rough humps. I can feel the knot moving within her pushing her walls out as it moves back and forth. She finally loses control and starts shaking like a leaf. Her movements lose cohesion and her pussy contracts around me like a vise. Her cervix slides along my shaft in time with her contractions.
Her legs slide off of me and I know it won't take much more for me, but I want her to get as much as she can out of the ride. I grab her ass holding her in place and slam into her continually. I only manage a few dozen thrusts before my balls empty into her shuddering cunt.
We both collapse back against the cushions and I sluggishly stroke her back and let her shake out the last of her orgasm against my shoulder. My cock slowly recedes into its home and the change starts. I watch my hands over Kristie's shoulder and the fur disappears into my regular skin. My mouth recedes back into its normal shape. Finally my dick pulls into my stomach and leaves my familiar lovely vagina in its place. Having a dick was fun for a quick fuck or two, but I definitely don't want to keep it forever.
Eventually, Kristie stirs. "Hoo. That hit the spot." She crawls off of my sweaty body leaking sperm on both me and the couch as she moves. "Several of them actually." She smiles and gives me a lingering kiss before climbing unsteadily to her feet. I scoop some of my sperm off of the couch and give it a taste. The flavor explodes on my tongue and I eagerly lick my fingers clean.
"I better go up and check on the little one. Try not to fiddle with our toy too much while I'm gone."
I watch her shaking her naked ass at me all the way across the living room, but I'm already clutching the See and Say before she reaches the base of the stairs. I give the dial a spin and pull the lever for one more go.