The end of the Age of Dinosaurs had come with a terrifying flash and a brittle cold shock that lasted for centuries.  The Earth for the next 65 million years would see a dynamic revolution, as reptiles who had once ruled the land would find themselves being slowly diminished, starved and frozen by the Ice Age that tore across the Earth, and wrapped it in a blanket of frigid death.
In this new world, what normally would have come after was the dawn of mammals, small hairy warm-blooded creatures who did not need the sun that was hidden beyond the great blanket of smoke that choked the light from the world.  They could scavenge, survive and hunt by themselves in various groups and, while much smaller than dinosaurs, were far more versatile.  But something would change in this Earth.
It all started with one particular creature, a Repenomamus which resembled a giant silver rat with a badger's head, around 3 feet in length.  Rhett had always been a strange one, a beast who always imagined what it felt like to be eaten.  Most creatures feared it, but Rhett found it fascinating, the way larger beasts would swallow his kind down in one gulp, those tiny screams disappearing in a bulging throat.
It became an obsession, a dangerous one much bigger than anyone would think.  Rhett, unlike most mammals, lived in a verdant paradise beneath the Earth itself.  One of the tectonic plates had shifted so far, that an entire world had fallen beneath the ice-encrusted surface that became a relic of prehistoric times.  A lost world where dinosaurs still roamed with huge ferns, dragonflies the size of cats, and enormous tropical trees that stretched towards the stone ceiling.
	"Hhhhokay, hoo...let's get one out before lunch, yeah?"
Rhett had been burrowing his way through the underground jungle, the light from millions of fractures leading to the outside world filtering in to give a vague semblance of daylight.  He found his favourite personal spot, a large allosaurus skull that had remained where it fell.
Slipping between the jaws, he pressed his body against the sides of the teeth that had blunted from decay, enough for him to savour the feeling of them digging into his fur with a gasping shiver.
	"Mmmmhhhh...h-haaah...ohhh yeah, d-do I taste good for you sir?"
His friends and family knew about this, for shame was not yet part of the evoluitionary construct.  They just thought it weird, stupid even that Rhett desired to be eaten, wanting to be slurped up.  But he was just weird and harmless.  For now.  As he started grinding harder on the teeth, turning erect with a panting whimper, he felt the crunching of feet nearby and his excitement turned to instinctive panic.
The smell of a Tyrannosaurus was one that all mammals feared.  But for Rhett it only made him throb with an aching burn that made him shoot his pre across the allosaur's jaw as he watched and waited to see the beautiful beast.  The tyrant lizard king, or in this case the queen judging by the scent, was 40 feet long and 26 feet high when she raised her head up high.
Her amber scales marked with maroon stripes down her back were surprisingly good at hiding her in the jungle, giant feet squashing the mud in giant clumps that spread round her toes.  The T-rex was apparently hunting something, a Steropodon that was almost exactly a platypus of 3 feet long who was soon trapped against a rocky wall.
	"HEY-EY, HEY, C-CAN WE TALK ABOUT THIS?!"
She snorted with a cold look, shaking her head.  The rex snarled with a deep shudder as she showed the side of ther body to the trapped monotreme.  She licked her giant teeth with her tongue, then strangely showed off her large winking puckered hole beneath the tail, with a look in her eyes back and forth.
	"U-uhhh...d-dammit," the platypus whimpered, "I...I-i don't like teeth so I guess...I'll go for the butt?  Least it might be...easier."
The rex smiled with a nod, and turned herself round to show her thick haunches.  Rhett was watching from inside the skull, amazed by this gorgeous beast and the offer she was making.  Any mammal that was cornered by such a superior beast would always submit in the end, it was simply the way of nature.  But the rodent was shivering harder with a throbbing in his cock, as he watched the platypus pull back against the musky hole.
Grinding her thick lizard ass against the monotreme's beak, the Rex shuddered with a moan as the inferior mammal turned his head away trying to resist.  But then he caught the scent of her depths, a strong deep spice that briefly made the platypus hear a bass tremor in his head from such overpowering of his senses.  He hadn't expected this, but knowing he was fated to die this day, there was a slow acceptance that came quicker than expected.
	"M-mmmhhhh...wow you...y-you smell real good...f-for a dino."
His mind became foggy with the musk, nuzzling his flat beak more eager into the swollen pucker that sucked and smooched his face, the powerful scent intoxicating him with such fervour that before he realised what he was doing, the mammal pushed himself inside and squirmed his head through the sphincter.  Once his neck was past the ring, she clenched and pulled him in with powerful muscles, flexing her thighs as the creature wriggled and whimpered with muffled sounds.
Watching all of this was Rhett, who gasped with surprise at a beast like him just giving himself up to the massive hole.  He crept closer to get a better look, peeking out the rear of the skull to witness the unusual end of the mammal.  The dark flippered limbs kicked and spasmed on the T-Rex's rump, gasping mutters and strange blissful moans rippling from within as his beaver tail flapped with instinctive desperation.
The platypus whimpered with fitful moans, his backlegs kicking faster as if thinking he could flee and trick the T-Rex, but her muscles were far too powerful the moment they hooked the beast within.  His beak snuffled and scraped against her anal folds, the mammal trying to push himself back but only ending deeper inside when the Tyrannosaur lifted her ass up to help him slide further into her depths.
Rhett was bucking against the side of the allosaur skull in his own heightening bliss, seething with envy at the lucky monotreme who could give his life so easily to the indomitable queen of Earth.  The dark flippered limbs of the platypus disappeared into her ass, a sucking gurgle faintly heard as his beaver tail flopped, and soon was swallowed up in her rump.
	"W-wow, hohhh jeeez A-AAAGH!"
He couldn't stop himself from cumming, spraying his mammal cum on the side of the huge skull with a trembling gasp.  When he finished bucking against the jaw's blunted teeth now coated in his seed, he looked up with a squeak at the T-Rex now staring down at him with deep brown pupils.
	"UHH...h-hi!"
The Rex cocked her head not expecting to be greeted.
	"I-i...I uh, saw you...eating up that guy.  It was really h-hot, does that sound weird, it kinda is, see I...I got a thing about...I always wanted to be eaten."
The giant queen smiled wryly with a little chuckle and licked her lips slightly.
	"I mean, you just ate right, I'm not gonna make you!" Rhett put up his paws bashfully.  "But well...i-it's always been a dream to wanna be slurped down a throat as big as yours but, wow...when you sucked up that guy in your juicy ass that was amazing, I-i never thought anyone could do that!"
She nodded with a swish of her giant hips behind her, a charming growl with a creep of her lip towards him.
	"I-i mean...I'd totally wanna be in there.  Can I see?"
She had never been asked this before, but certainly wasn't going to refuse.  She turned herself round and exposed her thick pucker, winking hard with the gurgling muffle of the monotreme still inside kicking away against her walls.  This in turn caused her to drip from her pussy, puffing up her scaled lips with a juicy slathering between her massive clawed feet.
	"H-hhhhh...o-ohhh damn you're beautiful," Rhett whimpered, "I...yes.  Ohhh yes this is where I wanna die, right in that thick gorgeous ass of yours."
With a lingering smile the Rex looked back towards him, swishing her hips teasingly and pushing her ass closer as if daring him to dive in.  But then she stopped, moving away and gesturing at him with her tiny but powerful arms.
	"Huh?" the rat shook his head.  "What's up?  You not hungry?"
The Rex rolled her eyes and vaguely spread her arms to try and encompass the world, then pointing at Rhett before she made stomping motions across the ground.
	"Uhhh, you-OH!  Ohhh you talking about the other mammals?!"
She nodded eagerly, scraping the earth and biting at imaginary things with fake swallowing sounds.
	"You wanna...eat...all of us?"
Her smile grew with a deep rumbling.  She pointed at Rhett, then walked over to tap the allosaur skull with a scrape of her claws.
	"And...if I help you, I get to be the last one ever, and you make us all extinct?!"
The queen stomped her feet with a happy bark, which deafened Rhett but also excited him with a trembling anticipation.
	"Hohoh, YEAH, ohhhh yeah that sounds awesome!  Wow I'm real glad I studied dino-charades, damn that...that's the hottest thing to imagine, I always thought about myself being eaten but...every single one of us mammals eaten until we're gone forever?"
The saurian licked her lips slowly with a fiendish grin.  Rhett smiled in turn with a gentle nod.
	"Alright...yeah.  I-i'll do it!  I'll help ya, means I get to watch what'll happen to me next as well, I know where a lot of us are, I'll lead them to ya!"
She bent down to snuffle his face with a soft lick, both in gratitude and also to tease him with the smell of her breath washing over his face, thick and meaty as his fur fluffed up and his cock shuddered erect once again.
	"H-h-hhhhh...ohhh momma, ohhh this is gonna be awesome, a-alright, I'll uh...I'll get started!  But...can I ask one thing?"
The Tyrannosaur nodded with pensive grin.
	"I-i...I want my family to be last.  I wanna know for sure we're all extinct, forever!"
She chuckled a deep tremble in her throat, nodding with another lick as they went to set their plan.

Over the course of several months, Rhett became a constant companion to the T-Rex, who he eventually began to call Momma for her girth and height.  She wasn't thick by Tyrannosaur standards, normally, but her unusual way of feeding through her anal walls gave her an unexpected thickness in her thighs, not fat but noticeably thicker than most T-Rexes.
The Repenomamus hunted across the ancient jungle for every mammal he could find, none of them larger than him as he would promise them food and riches.  With his reckless wile he found it much easier than expected to lure the first mammals, rodents and monotremes, large rats and slender shrews who were promised food and shelter.
But always there was the Rex waiting for them.  She would find a good place to trap mammals in, and he would guide them to it.  Across the length of the jungle, over days and nights in the underground, they searched and hunted and eradicated every single mammal with Rhett's skilful tongue, and the Rex's juicy thick pucker.
For an entire six months, Rhett was missing from his local grounds, his mate starting to grow concerned as the small badger-rodent rooted around in their territory, blissfully unaware of the quiet extinction of their kind.
	"Haaah...another day...another meal for one."
Moving towards her little cave, she dragged a compsognathus in her jaws and started to eat by herself.  Her snout was daubed in rich red meat when she peeled off the scaly skin and dug into the innards.
	"Ohhh Rhett...I knew you would be so foolish one day...at least you didn't leave me with children so...I guess I can start another family elsewhere."
She soon picked the bones clean and started to fall asleep, laying on her side as the evening crept in with a touch of darkness.  Suddenly she stiffened her hairs, snapping her tail at a familiar scent as she raced out of the cave and found her mate approaching.
	"Wha-...Rhett!?"
The lonesome mate galloped over to him, almost bowling over Rhett as he nuzzled and licked her face.
	"Where have you been!?" she cried.  "I thought you got eaten, or worse!"
	"Hahaha, well you're not too far off," Rhett rolled his eyes, "sorry for being away, I was on a real big mission."
	"What sort of mission?  Did you find another cave?"
	"Well it's LIKE a cave, technically, a nice snug and warm cave where all of us are going."
	"Wait...are we moving?" his mate sniffed over his face.  "You smell different, more...meaty."
	"I thought you liked meaty, Sara," he grinned waggling his eyes, "anyways, I got a surprise for you, just get inside the cave and I'll show you."
She rushed back in the cave, a small burrow shaped like a hill with a front entrance as Rhett motioned someone from the bushes.  Stepping forwards to stand guard at the entrance, the silver badger-rodent introduced them to their fate.  Large shudders quaked the ground as Sara became nervous, twitching ears and tail as she saw the pair of giant feet crunch behind Rhett.
	"RH-RHETT, RHETT GET INSIDE!"
	"HEY-EY, hey...it's cool."  He smiled serenely.  "We're all going someplace real special...right inside Momma."
Bending down her head, the T-Rex smiled with a large hazel eye glaring upon the mate who recoiled with fright.  She gave a soft lick to Rhett's head, much to Sara's surprise as she walked forwards.
	"What is this?  Rhett?  What...what did you do?"
	"I met this big Momma," he nuzzled the Rex, "turns out she's hunting all of us mammals, to wipe us all out."
	"W-wipe us out?!" she gasped.  "What do you mean?"
	"I mean all of us, gone, forever," said her mate swishing his tail, "because Momma here's a superior predator.  We've always known the dinosaurs were better than us, so much smarter, so much bigger so...why keep fighting?"
	"Rhett, what are you-...are you saying we should LET that thing eat us?!"
	"Yep!  The dinosaurs wre always better than us, we can only keep living for so long before we just...accept our place.  No more mammals left."
	"But that's absurd!" the wife shouted walking up to him.  "How can you just do this to us, you can't just say there's no more mammals left!"
	"No?"  Rhett grinned looking up at the Rex.  "Show her Momma."
The tyrant lizard queen who had been watching from the entrance gave a snort and a nod, turning herself round with lumbering steps that shook their feet as her giant claws twisted on the dirt before she bent down her legs to expose her thick monstrous thighs.  Her ass was ginormous, her pucker swollen up with a puffing wink that slowly relaxed to open wide.
With a shuddering clench in her sturdy legs, the Rex presented herself as Rhett motioned his mate to look in closer.  There were bones inside her gaping tunnel, dozens upon dozens of skulls and fractured limbs staring back at them, a graveyard in her folds with every skull they recognised as their own.  Endless mammals, shining white skeletons littered throughout as the family's eyes widened.
	"O-oh...oh my goodness," Sara shook her head, "how is...how did she-"
	"No idea," Rhett lied with a smile, "but she showed me, Momma said it was going to happen either way, and she's eaten up every single mammal out there in the world.  Now it's just us left."
	"No, no that can't be true, can it?!"
	"It is, Sara.  She showed me, didn't eat me cuz she wanted to show me what was going to happen to all of us.  I did ask our family be the last though, just cuz, if we're gonna die, we should be together right?"
	"So...you want...you want we should just...die?"
	"I mean you can run," he shrugged lifting his forelegs, "but then she'll eat you, and it'll hurt a lot more.  You know I'm right, don't you Sara?"
Rhett looked towards his mate who was struggling with the choice.  As odd as her mate was, his words were resolute, she could tell when he was being silly and this was not one of those times.  The puffing pucker of the T-Rex showing their future was both startling and yet oddly enticing.  It almost felt like a relief, knowing they were the last of their kind in existence.
	"Well," she sighed shaking her head, "if...I know you wouldn't lie to me dear, and if...this dinosaur is giving us a chance to go peacefully it's better than what we normally would get."
	"Right!" her mate nodded.  "It's the best chance we'll get without it hurting, and well, with only our family left...breeding's not gonna happen."
	"That's true...alright."  She gave a gentle smile.  "Now I know why you never wanted children."
	"Heh...guilty as charged."
He stepped to the side as the Momma Rex looked behind her, swishing her tail slightly with a seductive purr as if beckoning them inside.  Sara came closer, sniffing around the musky hole with a strange shiver through her body, a twitching gasp as something filled her senses.  That natural subservience, that all mammals felt beneath the scent of dominant superior beasts.
Sara pushed her head in, feeling the muscles suck around her neck and pull her inside with a soft squeak of surprise.  Her paws gripped against the "ground" of the anal tunnel, hot and squishy under her feet as Rhett watched on.  The Rex moaned with a shivering excitement, her pussy dripping out underneath to sully the earth in a drooling puddle.
	"You alright?" Rhett asked.
	"A-aah!" she gasped pushing in.  "I-it...feels rather slimy, but...strangely nice."
	"Go in deep as you can.  Wanna make sure there's enough room for me."
Kicking her back legs, the mammal pushed further inside with her paws slipping against the bones of her fellow kind, skulls covered in musky slime as the walls trembled from Sara's squirming touches.  From outside Rhett watched her legs pull up inside, swallowed by the hungering maw of the Rex's anal bud, inch by inch.
	"There she goes," Rhett said dreamily, "aaah...ohhhh, this is the hottest thing I've ever seen."
	"R-really?" Sara cried from within.  "I...I'm not sure how but I'm starting to understand...why you wanted this."
	"Of course dear...I'll be happy to watch you die, with the rest of our kind."
She smiled not quite understanding his sentiment, but gladly stuffed her pale furry body into the pulsing ring of the Tyrannosaur, who stiffened her tail with genocidal glee.  The Rex wondered if it was hereditary, in which case all the better as she lifted her ass to flex her muscles and pull the beast inside as she found her paws slipping.
The bones scattered under Sara's feet as she squealed with excitement, her tail gulped up in a slurp with a muffled laugh as skulls rolled past her body.  They were strangely soft and pliable, the musky juices of her anal depths helping to break down the remains of her kind into blunted fragments and scattered dust.
	"A-AAAH!  OHH, o-ohh goodness Rhett, Rhett I'm...I-i feel so wet."
	"You get used to it!" he cried from outside.  "Just lay back and accept it."
	"N-no...I mean I'm...wet."
	"Oh."  He tightened his legs feeling his cock peeking out.  "Ohhh...you liking this Sara?"
	"Let's be honest," she called louder from within, "you wanted this didn't you?  I know this was a dream of yours."
	"I mean, yeah it is," he grinned bashfully, "but if we're all gonna disappear, we might as well make it easy."
	"I know...in that case, can you...breed me, inside of her?  Just once, just...if we're going to die, I want to feel you cum inside me before we do."
	"Oh.  Yes."  Rhett stiffened in his shaft.  "I would love to breed you inside of Momma Rex, let me just...thank her, before we do."
Walking round to the giant Tyrannosaur head, he gave her a sweet nuzzling lick as she did the same, her tongue slurping across his entire head with her thick meaty breath washing his face.
	"Thank you," he murmured, "I'm so...so glad I could help you end my kind."
She purred a lewd chuckle and clenched with a sudden crunch, one of his sons suddenly squeaking with a crack in her lower abdomen as Momma spurted more of her jizz from her pussy.
	"Do they feel good inside you?" Rhett gasped stiffening erect.  "Hohhh...you been wanting to exterminate my family for ages huh?"
The Rex nodded with a wide grin, licking him again as he licked her tongue.
	"I'm glad we're all extinct.  All us filthy mammals...hope you enjoy our last moments Momma."
She growled with blissful content, watching Rhett crawl back to her giant thickened rear and embrace eternity inside.  He was already spurting from arousal, his dream finally achieved at the greatest cost.  Climbing inside with a full shove of his body, the last Repenomamus gave his life willingly to the pleasure of a superior species, the Rex moaning louder with a sopping drench of her cunt juices underneath.
Panting with bliss, the saurian clenched harder to pull him inside, feeling the mammals squirm and creep into her darkening depths as the muscular walls sucked and squeezed and cradled them amongst the bones of their kin.  A wondrous bliss filled her from feeling the last of these mammals so gladly walk to their impending death.
Such inferior beasts, wretched filthy warmbloods that while were delicious, felt so much more wonderful when they stuffed themselves inside her tight warm crevice.  Inside her body, sliding forwards into the deep musky trench, Rhett found his mate laying on her back as she exposed her flowering pussy, surrounded by the bones of their kind to soon be erased forever.
	"I'm ready dear," she spread her legs with a twitching cunt, "let's make our last night...the most special one we have."
	"I always knew it would be," he gasped crawling on top of her, "I loved you Sara...thank you for dying with me."
She grasped one of the skulls, digging her claws into the eye sockets for purchase as she clasped it to her belly, and Rhett shoved himself into her sweet pussy.  Her cries of heavenly bliss filled the air within the thick anal tunnel, watching her mate pounding her harder than he had ever done in his life, the apex of which was everything he had wanted.  To feed another beast, a wondrous predator queen who shuddered from their lovemaking that Momma felt in her ass from their twisting furry bodies.
Rhett hammered his cock inside Sara, moaning louder with her as they savoured the heat of the monstrous tunnel, thick and voluminous with muscles hugging their bodies tighter and tighter, as they were pulled deeper into the darkness that claimed their entire race, the sound of a soft crunching bone from the abyss as the Momma Rex clenched hard enough to crack and twist the skeletons inside.
	"HOH!  O-ohh goodness!" Sara gasped.
	"MMMPH, o-ohh yes!" Rhett shivered.  "YES, a-aaah!"
	"I can't...c-can't believe there are truly none of us left...ohh...ohhh Rhett!"
	"I've never w-wanted to die, m-more than ever before this, AAAH!  Ohhh, d-damn, you're so beautiful like this S-sara!"
	"I...I'm glad we're going together."  She licked across his neck.  "Take me...take me before we're gone forever."
	"I will...haaah," Rhett kept pounding her, "n-nothing, of us...will be left."
They fucked to the height of their passion, the sliding grip of the Rex's anal walls pulling them further within as every thrust from Rhett pushed them deeper.  The Momma Rex whimpered nearing her climax, panting with a drooling tongue as she raised her ass high to feel the last of the mammals slide quickly into her bowels.
Rhett would cum the moment they pressed up against the bodies of their kind, the grim sight of his future destroyed sending him over as he came with a heartening cry and filled his mate to the last.  Such a cruel irony he loved, filling her with life whilst he savoured their death, and when the Momma Rex felt their bodies slump from orgasmic tryst, she crunched her muscles hard, and snapped their bodies clean like brittle twigs.
She finally came when she felt their movements cease, a flooding gush that sprayed into their home and washed it clean of all trace they had.  Every scent, every pawprint, gone in an instant as the T-Rex sighed with her thickening cuntlips puffing harder with the silken rush of her climax.  Her ass clenched hard as it could to make certain that the last of the mammals were fully extinct.
It was the greatest day of her life, next to her children being born.  All of the warmblooded vermin had marched into her body, and buried their remains within her juicy anal walls.  Now the Earth had taken a different turn in its path, as the Age of Mammals would never come, and their bones would soon become dust, scattered across her inner folds.