"I was going to show you this later, but now seems more appropriate" Eric excitedly stood too, towering over Smelly Rat and fumbling with his pants. Smelly rat shuffled and bit her lip in anticipation of Eric's impending reveal. She held her breath and puffed out her chest as he hooked fingers in the waistband; and she squealed in delight when the pants were dropped, revealing a hairless sheath with a curved tapered cock tip poking from it.
"Oh yes-yes! That looks just like the dildo Eric." She frantically clapped her hands, and went to step forward. Eric put his hand up however, "Wait, if we're doing this I'd have to make some changes. Thinking about how it worked last time it was from rat cum yeah?!" She nodded in agreement. "Yeah, I think that's what did it."
"I'd better get rat balls to add to this so. Give me too seconds". He ran over to the Chronivac, fiddling through the settings for a few moments, during which time Smelly Rat, super eager, pottered over to Eric's bed, climbed up, puffed pillows, lay back into them, and pulled her legs up to her chest, exposing herself.
"I see the scrub/no scrub option from the last time. Time to go with it off" Eric replied, standing and hitting enter on the machine. Immediately he wobbled on his feet.
"Oooohh" Eric moaned, legs spreading. Both watched in awe as his balls elongated and grew, and grew, and grew, until they were the size of cantaloupes and visibly weighing him down.
"Oh fuck, I forgot how big rat balls are in comparison!" Smelly Rat squeaked in delight.
She wiggled her fingers and toes at him and purred, "come fuck me big boy. Make me a smelly, furry rat.". Her smile was bright, but her chest was heaving and stomach shaking in excitement.
Eric climbed on top of his squeaking and squealing girlfriend, his cock fully out of its sheath and hovering between them.
Their eyes met for a moment.
"Last chance, you sure?" He asked.
She exhaled loudly, "I am"
"We don't know what part of you changes permanently next, could be anything." He added.
"I know." Smelly Rat churred, grinding her hips. "Now stop hesitating, and fuck me!" She demanded, her hands scrambled to find his cock and guide it to her flush pink slit.
The pointy tip entered without her feeling much on anything, but that was expected, it was the feeling of the fully inserted rat cock she adored. Holding the base of the shaft steady she scootched down, pushing against it, just as Eric sank in to her. She let out a looooong moan as her boyfriend slide further and further in, tip penetrating, and tapered shaft widening the deeper he went. The silky smoothness of it was a delight, and on and on it went until, just as Smelly Rat thought she would burst, the tip found her cervix the same time their hips collided.
"Unnh... gods you're the perfect size for me...." she let out exhilarated. Leaving go of his abdomen and reaching under to feel his enormous glossy balls. So large were they that the skin was pulled taut and looked shiny.
Eric for his part then put a hand on Smelly Rat's chest, running it up and down, playing with her many many nipples. Smelly Rat arched her back and leaned into it moaning. "Oh god. Oh god. So many! Feels so good" she let go of his balls, grabbed his face with her hands and kissed him hard. To which Eric responded by pulling his hip back slightly, pulling a few inches out of Smelly Rat, before slamming back down, making the mutant jiggle and squeak in pleasure. He straightened up, staying in her, grabbing her by the soft meat of her thigh with his now free hand, holding her in place as he picked up a rhythm.
Smelly Rat, now finally feeling a live, warm version of the rat dildo she had been playing with the last while was absolutely in rapture. Her face was one of abject pleasure as the smaller, soft, mutant was jostled around by Eric's rough thrusting. Every jolt one of delight, every poke of her deepest insides just right. She felt her entire body jiggle and jolt at every thrust, and knew it was quite a site for Eric.
As the minutes passed and the rhythm built, so did Smelly Rat feel something building in her, a bubbling sensation in her stomach and chest, an excitement that this was it! All of those ignored and denied nighttime fancies now being played out. The old Lisa would have been so disappointed in her giving in, but the new Smelly Rat was really getting off on the idea.
No temporary messing around, having some fun and changing it all back. No safety net that a system reset would turn everything back the way it was. This was all permanent, which made it all the more impactful to her.
She was forever going to change her body, mutate her DNA into a completely crazy rat creature, not this barely odd looking set up she had now with big ears, an upturned nose, buck teeth, extra nipples, and long toes. Bar nipples any other one wouldn't even raise much of anything for any random passers by.
But now... if she looked like those anthro creatures, a reality would see her an unrecognisable mutant to her family. No normal life. No normal job.
Her feet hooked behind Eric's back, pulling him in needily and clawing at his sides.
"Do it. Do it! Cum in me!!!", she begged him. "I wanna look like I do in my dreams!!!"
As soon as she began begging to be turned. Eric's new enormous balls tensed, ready to dump their load. He grunted in pleasure, signalling to Smelly Rat how close he was, which just made her grip him tighter.
"Fuck... yes-yes! Deep! Cum! Yeah!". Both pressed their bodies fully together, sweating, heads on each other's shoulders, moaning into the others ear. Eric's hands were fully grasping Smelly Rat's soft ass cheeks, kneading them needily. While Smelly Rat scratched and pawed at Eric, desperately trying to draw him in deeper.
"Oh God! Yes! Cum in me, please! More ratty!.". She clenched hard, pulling him into her body, grinding her hip wetly against his. The desperation was too much for Eric as his enormous rat balls boiled over, and with a juddering cock he released his seed into his girlfriend.
Smelly Rat felt the injection of warmth deep inside her and began babbling in orgasm, "Oh fuck! It's in. Yes! Hnnnggh! Yes-yes! Love you. More. Cum!". Eric then silenced her with a long drawn out kiss as both came for what felt like an age.
Eventually the kiss broke as both came up gasping for air. Smelly Rat had the widest grin on her face. "Oooohh.... Yeeeeesss.... I can feel my womb is filled to the brim. You came more than TomTom did." She gently patted her soft abdomen. "I wonder how much this will do!?" She giggled nervously.
"I don't know, good question! How long until, well, you know." Eric asked, pulling away from her embrace. Smelly Rat for her part immediately leaned back, legs in the air, desperate to hold the cum inside herself. "It took quite a while for everything to be absorbed from TomTom. Maybe tomorrow morning by the time it's all gone through."
"Oh man... I don't wanna wait that long." Eric laughed. "After all this time I have to wait again!" He chuckled.
Smelly Rat's head cocked, picking up on something, "All this time? Eric, how long have you wanted me to change"
Eric went beetroot red, but looking at a mischievous Smelly Rat he decided to be honest. "Eehhh... A good few weeks, maybe two months ago I started wondering what you would look like more like a rat, and got very into it."
Smelly Rat chuckled," well, now you find out." She hugged her legs closer and held them in place smiling lovingly at her boyfriend. After a few more moments she let her head rest back into the pillow and sighed loudly. "Aaahhh..... Can't believe I'm actually finally doing this. It's been eating me inside for so long..."
Eric hopped onto the bed, lying beside Smelly Rat, he kissed her softly and said," now it can change you inside instead. How do you feel?" He added.
She turned her head. Eyes lidded. "Exhausted now, excited. But tired. I'm going to crash soon."
Eric pulled a blanket around them and snuggled in to her. "We'll just rest up a bit" he mumbled, getting tired himself.
---
Eric's dreams were filled with images of making love to a furry anthro rat, each time becoming more and more animalistic looking. Eventually he half woke in the pitch dark to shifting beside him. Smelly Rat was moving and snuggling into him. He must have made a noise as the movement momentarily stopped and he heard her mumble. "S'working Eric. I feel it... Feel... Better". Her arms wrapped around him and he felt her soft stomach, dotted with nipples press hard into his crotch and abdomen. It was only then it dawned on him that his temporary rat cock was fully extended from it's sheath, a hangover from his vivid dreaming.
His Rat girl pressed against him started grinding and moaning, riding her soft body up and down the slick shaft. "Cum for me..." she whispered into his chest, licking his nipples in the dark. "Can I see you" Eric whispered. He felt her shake her head in the dark, "I'm not ready yet.", her hands expertly ran over his shaft, releasing a large squirt of precum. "You're ready though, she whispered and her head went under the blankets.
Within moments he felt her tongue and mouth eagerly licking and sucking his shaft. It took only a few heartbeats till he was grunting and cumming directly into her face and mouth. As he came he imagined dumping his load in the rat faced anthro of his dream, knowing full well she was not that.
At first there was a cough and a muffled. "Ack..." a deep inhale and then a mumbled, "was not ready for that taste".
"All okay?" Eric mumbled sleepily in the dark. There was a shuffle under the duvet and a, "tastes a good bit different to human cum. Will come around to it," piped up from underneath. A few moments later tentative licking around his shaft began.
"When do I see you?" Eric asked the blanket.
"Hehehe... Eager aren't we!?... morning... Need more time to change... You're gonna like it..." She was shaking in giddiness. The licking and cleaning now sped up as Smelly Rat finished cleaning up his rat shaft. At the end he felt her face nuzzle into his rat balls, and heard the sound of her inhaling deeply.
"You'smell soooo good.", Smelly Rat lisped quietly before sighing and scooting up in the dark to pop her head out of the blankets.
Eric was immediately stung by the acrid smell of rat cum, as Smelly Rat gasped for fresh air. Her cum smelling breath fell on him then too and he coughed, "God you smell like Rat cum, enjoy it?"
He heard her chuckle, "ohhhh yeah. Tastes very, very, strong. But, I think, considering how excited I still am at the thought of more, I like it!"
"You're insatiable!" Eric exclaimed, "A total degenerate!"
Striking Smelly Rat's masochistic tendencies she shuddered in response. "I am a degenerate," she whispered, "what gave it away? Willingly devolving into a rat so me and my boyfriend can live out our kinks?"
Eric laughed to himself and let Smelly Rat snuggle into him. "Yeah, I suppose that about sums it up!"
A comfortable silence descended, and before long both drifted back to sleep.
---
Dawn broke to a cold bed as Eric turned around and found it empty beside him. He panicked a moment, thinking she had shrunk to Rat sized before he realised the shower was running. Grinning he got up, heartrate picking up pace. He padded across the room, reaching the bathroom door and throwing it open, just as the sound of running water stopped
A haze filled the room and from the depths of it, stepped Smelly Rat, formerly Lisa, in all her glory.
Eric gasped in delight. Where before she had looked human, with a few oddnesses that each individually wouldn't be unseen in any random human, now she was unmistakably mutating into a rodent.
Her ears went from large human ears, to a small dish shape, and stuck out from her head. Her upper lip went from prominently buck-toothed, to now actually beginning to jut out, with a puffy philtrum, the real beginnings of a muzzle. The nose too was now upturned and pinched into a snout shape.
She smiled at him with the unfamiliar mouth, raising a hand. On it he saw her nails looked black, hardened, and swollen. A quick glance down confirmed her toenails had a similar fate, only there the toes themselves looked completely different. Fully elongated now with the big toe shifting to the side, making her feet look far more hand like.
He picked something up as he scanned down, now glancing back up, all of her pubic and body hair was gone leaving her body fully smooth and pink.
Smelly Rat picked up the puzzled look on his face and spoke first, "I didn't shave it, it all came out in the shower, I think it might be getting ready to be replaced!"
"Woah!" Was all Eric could say, "you look absolutely amazing"
Smelly Rat beamed in delight, "looking much better now for sure!" She did a quick spin, the tiniest bit unsteady on her newly shaped feet. "Defo not human anymore, your girlfriend is going to be your ratfriend from now on."
"Hahaha, you definitely look amazing babe, you still loving this plan? How do you feel now about going further?"
Smelly Rat had fully closed the distance and leaned up to whisper to Eric, "oooooohhh yes. You'd better be ready with those balls, because I'm going to be draining them dry for the nedlxt few weeks."