"Hello and welcome to my demonstration on how scat-morphs, or scathros are made! I'm Julia, and I'll be leading you through the process." 

The nude, brown dragon waved to the camera.

"In case you want to know my credentials, I am a scathro myself, obviously~" She ran her fingertips across her body, from the curve of her bouncing breasts, down her belly to her swinging futa shit-cock. She turned and spread her cheeks to show off her brown-slick pussy and dark donut.

"To reiterate, a scathro is a living being composed entirely of excrement. The entire body you see is formed wholly of hot, 'living' shit. As such, I can eat the poop of others for my own nourishment. If you shit on me, that's an appealing and arousing snack~"

She winked, then stood up straight.

"To business! There are many different ways that scathros can procreate. Some big, slimy ones can split into multiple identities. Some rare scathros can have anthro-like sperm that causes regular pregnancy, often creating a hybrid. Some who are more tentacle-like create parasitic eggs that are carried by hosts."

She listed them out on the whiteboard, following through diagrams of anthros being roughly fucked by scathros, the scathros drawn out in brown marker pen. 

"But I'd like to demonstrate a method that comes natively to my 'subspecies'." 

She tilted the camera to the side, showing a slender male rabbit tied up in bondage gear. He was trembling, but his dick was standing proud. 

"This is one of my pets who has been [i]begging[/i] for a good breeding. Haven't you, Dylan?"

She pulled the wet ball-gag out of his mouth. The rabbit panted. "Y-Yes... Mistress...!"

"There's a good boy!" She tickled him under the chin. "Then get on your knees."

The rabbit promptly dropped, keeping his mouth open wide. 

"The first step is to create a firm base for the new scathro. This will serve as a protective shell for the body while it grows, and also as building material for the body itself. And it need, you guess it, fresh shit!"

The patted the bulge in the rabbit's belly. "Dylan here has been plugged up for a whole week preparing for this. Got your bowels nice and clogged with hot, steaming poop, don't you~?"

The rabbit whimpered and nodded. Julia grinned and stroked his head. Then she turned to the camera and put back her teacher persona.

"Now, this is helpful, but it isn't strictly necessary."

"What?!" The rabbit squeaked, but Julia shushed him.

"Because far more poop is required to make a new scathro than any anthro could normally build up. So it is the job of the scathro to make the fertile soil, so to speak!"

She squatted down, planting her wide behind right on the face of the rabbit. She gave a happy little grunt as she pushed a muffled fart right into his face. 

"Good boy, Dylan, open wide! Eat up every scrap of momma's shit!"

[b]schblrblrrrrplrrplrplrrrrpch[/b]

The rabbit's throat bulged out as he struggled to swallow each thick log Julia pushed into his mouth. Shit-dragon and rabbit both stroked their cocks as one gave the other a stinky feast. The rabbit's belly grew rounder, full of the dragon's muck.

"Phew!" Julia finished and stood up, leaving the rabbit panting, gasping, his mouth ringed with brown. "Look at that belly! That's a very good start. But..."

She went behind him and gently pushed him forward, lifting his hips up into the air. From his hole she pulled out a thick, metal butt-plug, leaving him gaping for the camera.

"For a proper job, your seedbed really needs to be filled from both ends!"

She grinned as she slapped her butt against the rabbit's cheeks, puckering her hole until their two asses kissed. 

Dylan moaned weakly as he was overwhelmed by the thick, musky logs pouring into his hole, stuffing his belly up from the wrong end. His dick throbbed as his ring was forced wide around Julia's shit. 

"You'd better not cum yet!" She warned. Dylan whined and took his paws off his cock. 

Julia was pumping her own cock as she shit, guiding herself up to full hardness.

When the rabbit's belly was round and wobbling with freshly-added shit-weight, the dragoness lifted herself off him. A tail-tip of her poop was poking out of his ass, trembling as his body was trapped between pulling it in and pushing it out.

She stood up, her shit-scales sweating a little, and fondled her hard dick. "Now that's a good-looking seedbed right there! You'd think he was pregnant already, looking at him, but there's one ingredient missing. It's scathro cum! It essentially serves as the nucleus for the initial scathro 'cell'."

Julia grabbed her hard dick for emphasis.

"But not just any cum. The scathro needs to be enamoured with a powerful urge to breed, they need to [i]crave[/i] it. Just a quickie in the bathroom stalls is not going to do the trick! Lucky for you, this one..."

The ran a hand across the trembling curvature of the rabbit's belly.

"This one has been teasing me for days about how much he wants to carry my litter. How he wants me to fuck his butt full of dragon eggs. As a result, my balls are full of potent, virile spunk. And I am fucking horny as hell!"

She picked up the rabbit and forced him down onto the table, spreading his legs to better see his trembling, shit-caked tailhole. 

"Now you're gonna get your wish!" She snorted, eyes ablaze with lust. "Everyone's gonna get to see you get bred by my draconic dick! I'll pump your bussy so full that you're guaranteed to get shit-pregnant!"

The rabbit was breathing in short, sharp pants as the dragoness angled against him, poking her cock against his twitching hole. He whimpered as she nuzzled the tip against him, teasing him, spreading him wide. Then his breath came out in a panicked gasp as she thrust herself roughly to the root.

"Take it! Take it you fucking slut!" She panted, drooling as she pounded him hard enough to shake the table. "You'd like to be a part of my harem, huh? No thoughts other than my dick. Waiting to eat my shit and take my dick and cream yourself with pleasure!"

The rabbit was mewling, biting his lip. Between his legs, his dick was dripping with thick pre. 

"Cum! Do it! Show me how much you love my dick in your ass!"

"[i]AHHHHHHHNNNGH~![/i]" 

Dylan moaned out lustfully as his cock erupted, spraying thick white seed over himself and the scat-dragoness. 

The display just made her pound him harder, slapping his cheeks firmly against her shitty hips, heated vapour visible as her breath came in super-heated pants. Brown sweat ran down her breasts as they bounced with each thrust. 

"It's coming! It's coming!" She growled, closing her eyes as she took him in hard, pile-driving thrusts. "Get pregnant! Get pregnant, get pregnant, get pregnant, GET PREGNANT!"

She roared as she came, Dylan's bowels becoming fuller still with syrupy brown cum. It spread around and into the titanic load of poop he was holding, until. 

"HNGH?!" He grunted as he felt it. A warmth growing from a point deep inside his bowels. 

Julia kept thrusting as she rode out her orgasm, making sure to empty her nuts inside of her willing sub. At last she finished, resting her body against his while keeping hilted inside him. She rubbed his belly, feeling the gentle heat blossoming inside.

"Mission accomplished!" She stood up on wobbling legs and let her dick slide out of his ass. She picked up his plug and crammed it back into his ass, forcing out a weak little whimper.

"When a new scathro is 'fertilised', the carrier's belly will glow with warmth as the new life integrates with its host. Dylan here will get to enjoy a growing craving to eat shit, sudden bursts of arousal, and pleasure so intense that he'll cum on the spot, among other symptoms."

Julia grinned, patting the trembling Dylan's rabbit butt. 

"That will last maybe two or three weeks, until the scathro is ready to come out, giving him a nice, big stretch!" She smirked, her dick giving a little twitch of excitement. "Now, how does that look? Why don't we come over here to another sub who I prepared earlier..."