(First half of the story was not written by me

A human with a rather embarrassing fetish turns to his roommate for an outlet.

He was on his knees, very quietly touching himself as he looked at the sleeping yellowish-brown dragon on the bed, wings furled behind him. Pyrrhia's back was facing him. His long tail flicked lazily in his sleep, the triangular tip leaving a crease in the mattress. Zion's face was inches--inches--away from his goal.

It may as well have been in another dimension. He didn't dare touch his roommate's butt, or move his highly obstructive tail to a more convenient position, out of fear of waking him. He moved his face in close, as close to the underwear-covered section as he could comfortably manage, always aware of his tail and heavy breathing. If the dragon so much as sniffed in his sleep, Zion would duck away and wait a few minutes before moving in again.

When his head was in range, he puckered his lips and kissed one of the buttcheeks in his face so lightly that he wasn't sure if he was applying enough pressure to kiss the ass under the tight cotton underwear. His cock jerked in his hand upon contact.

He tried to move his face closer to his roommate's crack without bumping the large tail. He had moved the tail with success in the past, but there have been just as many times when his roommate jerked awake and felt for whatever was touching him in the dark. He would duck away the split-second before his roommate's hands would discover him and crawl out of the open bedroom door, his heart screaming "URGENT" in his chest. As far as he knew, he had never been officially caught-- Pyrrhia never brought it up, anyway.

On those successful nights he would gently put his hands under the wide base of the tail and push up, just enough to fit his snout under; not an inch more. Then he would withdraw his hands and slowly move his head in until his nose touched the underwear just above his roommate's asscrack, inhaling the stink through the underwear, resisting everything in his body begging him to just rip off the garment and bury his head in the beautiful, forbidden ass.

Tonight he couldn't get close enough to sniff, though he could barely see the inward indent of the underwear pressed into the crack. . .then the big tail in his way twitched, and he heard a soft "pffff." The smell followed immediately; the overpowering stink of Pyrrhia's gas filled his nostrils, mouth and head; his eyes rolled back as he quietly inhaled the last traces of the stink in the air. His cock was stone-hard and aching for a rubbing. After a quick and futile sniff to see if he could get any more of his roommate's wonderful scent, he slowly backed away and crawled out of the door, too tired for any further adventures. 

Later, Pyrrhia eventually found out about Zion's fetish. Zion expects him to be angry, but the dragon is unexpectedly kind to his human friend, and decides to give him what he wants.

"I want. . .I want you to sit on me. . ."

Pyrrhia turned and squatted slightly, exposing his ass. Zion could see his roommate's tailhole, tightly closed above him and crusted with dung, waiting.

"Tell me how beautiful I am," Pyrrhia said.

"Oh, God, you're the most beautiful thing in creation; your ass is perfect, so perfect, you're a god, Pyrrhia, please, let me worship you, pleeeaaaase. . ." 

His roommate's ass lowered, slowly; Zion lifted his head to meet it, then it settled down on his face. He felt his roommate's cheeks clench together on his snout as he sniffed, inhaling as much ass stink as his lungs could hold and exhaling and inhaling again; every breath he took was Pyrrhia's ass; it was his air, now, he needed nothing else. He nuzzled his nose in his roommate's asshole, heard the dragon above him grunt and moan slightly as he spread the cheeks apart. He kissed the wet, puckered hole, tasted the sweat gathered there. The hole was laden with dried dung, which Zion was also able to taste. He briefly wondered how the dragon was this lazy about wiping his ass. He was relatively clean in nearly every other regard, and Zion was unable to understand why. However, he did understand one thing. He wanted more.

He felt Pyrrhia adjust above him, shifting his butt to stay on Zion's face while he bent over. He felt a hand grab his foot and pull it up between his legs, then something wet sliding across it from tip to base. His roommate took his foot in his mouth and sucked on it, moaning, rubbing it down with his arms and brushing against Zion's asshole, cock and balls.

Zion took one of his hands and slid down his roommate's ass until it found his balls; he held them in his hands and pulled slightly as he sucked on Pyrrhia's anus. The dragon above him growled again and he felt his own balls fondeled. His cock was ready to blow, overloaded with a pleasure Tio never thought he would experience: his face buried in his roommate's smelly ass, his nostrils wet with butt-sweat, his lips kissing and sucking on the most private and desired part of Pyrrhia's body. He licked the hole, pressed his tongue against it. He felt the heat of his roommate's body as he pushed his tongue gingerly inside.

"Nrrg, don't do that," He vaguely heard his roommate say. "I gotta--HOLY GOD!"

Suddenly his ass loosened around Tio's tongue. He pulled out and opened his mouth as the big dragon farted on his face.

"S-sorry, Zi, I GOD DAMN IT GOD SO GOOD!"

Zion attacked his roommate's ass then, breathing in his gas and shoving his nose against the hole, hard, pushing his tongue deep inside, not caring about anything but the stink enveloping his existence. He smelled it, he tasted it, and when he could hold on no longer he pulled his face out of Pyrrhia's ass just long enough to moan.

Pyrrhia looked over his shoulder at the human. Unbeknownst to him, his digestive tract was backed up with more than just gas. Pyrrhia was unsure what to do. On one hand, he could simply alert his roommate, pause their fun, and go use the restroom. However, Pyrrhia could feel the waste moving quickly towards the exit, and knew he wouldn't be able to make it to the bathroom in time. He hoped that the human would be able to take it.

Zion was happily continuing to taste and slurp at Pyrrhia's pucker, attempting to swallow every drop of old scat and musky ass sweat that was available to him. The hole stretched out once more, and Zion suddenly got blasted face-first with another loud fart. This one was much wetter, splattering Zion's tongue and open mouth with the dragon's ass juices. He swallowed with some difficulty, as licking up the sweat from Pyrrhia's crack was far more difficult than eating liquid straight from his asshole. Pyrrhia grunted, and farted once more. The fart started out very dry, then got wetter and more nasty until suddenly stopping with a wet squelch. Zion stopped rimming the dragon as he felt the hole begin to pucker outward. Pyrrhia lifted himself up slightly and began to push, forcing the log out of his asshole and into Zion's mouth. Zion opened his mouth wider. The wet, barely solid turd tasted horrible, and was laden with heat from the dragon's fiery digestive tract. However, Zion was overwhelmed with a sense of pleasure in being able to help his roommate in such an erotic way. The log fully detached from Pyrrhia's asshole, and fell into Zion's mouth. Zion closed his mouth, chewed, and swallowed. As he opened his mouth again, Pyrrhia dropped back down and pressed his ass directly against the human's open mouth. Pyrrhia grunted, snorting smoke out of his nostrils as he pushed on his gut. The dragon passed gas directly into Zion's mouth, then sharted a wave of diarrhea down his throat. Zion coughed and sputtered, unprepared for so much waste. After he eventually managed to swallow, he heard Pyrrhia's wings unfurl and flap a few times, trying to clear the air in a futile manner. Zion was dazed, laying there with his mouth gaping as his mind admitted one thing.

He and his roommate were now the only two people in the world who knew his secret.