Instincts

Greg worked his tongue gently around the balls in his mouth, feeling them shift and move. He knew how sensitive they could be and the urge to bite was nearly overpowering so he pulled off. The smell in the air was making him drool. He wanted. With no hesitation, he pulled Thomas' dick into his mouth. When he tried to go down completely, he nearly gagged so he backed off. Thomas let out a soft "Oh!" before gripping Greg's hair. Greg slowly pulled the cock into his mouth, working his tongue around the shaft.

"No... oh god, no teeth... no... oh oh... no teeth..."

Greg pulled his teeth back and used his lips and tongues to caress Thomas' cock. With one hand, he pumped the shaft while he pulled his head up and down on the man's dick. He could taste the salty pre-cum but it didn't bother him. He wanted more. His own erection throbbed painfully in his pants and he wanted this man to cum in his mouth. The smells, the taste, the sex, the raw sex, he wanted it all. He pumped the cock harder and sucked on the tip of the man's penis. He worked his way back down and then up, licking and sucking. Thomas cried out as he came suddenly. Greg swallowed the salty load several times until his mouth was clear.

"Fuck! Fuckfuckfuck!" Thomas screamed. "I'm sorry! I'm so sorry! I didn't mean..."

Greg pushed him back on the couch and stood, taking off his own shirt. His fingers itched to claw the hairless flesh beneath him.

"Are you... are you growling? Are you okay?"

Greg grinned. "More than okay. Undo my pants for me."

Thomas leaned forward eagerly, his flaccid penis still dribbling cum. His fingers worked deftly and soon Greg was stepping out of his own pants. Greg's own body was covered in hair. His chest was thick but soft with hair but he kept his cock trimmed when he could. Thomas grabbed Greg's eight inch dick and leaned forward to suck on it. Greg grabbed Thomas' hair and pulled him back. "No." He growled, his lips pulled back to show his teeth. Thoughts were hard with the smell in the air but he burned with need. "I want to fuck you. Give me your ass." Thomas' face flushed with excitement. Greg could see the other man's dick trying valiantly to grow hard again.

Thomas spit on his hands and rubbed Greg's dick down. He leaned forward on the couch with his ass in the air. From here, he did almost look like a woman. His skin was very white and nearly unblemished. Greg could almost imagine he was fucking a woman. But, he didn't want a woman. He wanted this man. His dick ached for release. Greg grabbed Thomas' ass and pulled the cheeks apart. Thomas reached around to grab Greg's dick but Greg growled again and pushed the man forward. His teeth yearned to bite something. Greg kept one hand on Thomas' ass and, with his other, he guided himself to Thomas' asshole. At the entrance, he paused. Thomas wriggled slightly against him, moaning in anticipation.

Greg, still growling, pushed himself in slowly, hissing his breath out as Greg's ass wrapped around his cock. Thomas' dick sprang to life and the man bit into the fabric of the couch as he moaned. Greg grabbed Thomas' hips and pulled himself out slowly. The feeling was incredible. He pushed in again but stopped before their hips touched. His fingertips dug into Thomas' flesh, kneading him over and over as he pulled out again. He couldn't hold himself back any longer. He grabbed Thomas' muscular side with one hand to pull him into a slightly upright position.

Greg leaned forward and bit Thomas, hard on the shoulder. Thomas shrieked and tried to bury himself on Greg's cock. Greg could taste blood in his mouth and he growled at the smell of it. He started pounding into the other man, his mouth still locked on Thomas' shoulder.

"Oh god! Oh Jesus H. Christ! Yes! Greg! Yes!" Thomas shouted. Greg licked the blood off of Thomas' shoulder and leaned back to concentrate on fucking the other man. Tendons strained on his arms from the effort of holding himself back. His whole body felt like it was on fire. He licked his lips in a circle, tasting blood and cum as he did. His canine teeth felt sharp, sharper than they'd ever been. He roared as he plunged, fucking the other man.

"W...wait... not so... wait!" Greg's hips slapped against Thomas. "It hurts! Wait!" Black hairs stood out on Greg's arms as muscles bulged. He could feel his fingernails cutting into the other man as he buried himself up to his balls. He didn't notice the blood as he pulled out. All Greg knew was fucking - fucking this man in front of him. The hairs ran in a wave up his arms to his shoulders and then down his back, a fine carpet of black hair mingling with his body hair.

His back cracked, forcing him to howl in pain. He didn't stop pounding. Muscles bulged along his biceps. His shoulders spread apart, pulled by muscles growing along his spine. He liked his mouth, touching his nose as his tongue grew. His nose felt cold against his hot tongue, cold and wet. He could see his nose pushing in front of his face, cracking his jaw as it did. Sharp teeth grew to replace molars as they fell out. More teeth filled the gaps as his face grew into a muzzle. Black fur ran up his neck to cover his face. When he licked his muzzle from the effort of fucking the little man in front of him, his lips and nose turned black.

Thomas was screaming in front of him but Greg didn't notice. Mating was Greg's only concern. Fucking. Scents were overpowering. His needs left no room for thoughts. He ran his right hand down Thomas' back and the thick black claws drew lines of blood on the white skin. A thick tuft of fur grew out from Greg's crotch, covering the base of his cock. The fur grew up the base of his cock to create a sheath around him. The base of his dick bulged and then grew into a knot as the skin turned a bright red color.

Thomas no longer screamed - he was grunting in effort. Red hairs sprouted from his back as the cuts from Greg's claws healed over. With a small 'pop' a bulge started at the base of Thomas' spine and slowly grew into a hairless tail, pressing against Greg's stomach. Greg watched as Thomas' hands convulsed over and over. Fingernails were pushed out as thick black claws grew from the tips of the man's fingers. Thomas had his face half-turned in a grimace of pain or pleasure. The man's jaw broke and then grew out into his own muzzle. When he opened his eyes, they were a deep coppery bronze color. Thomas slammed back against Greg.

Greg gripped Thomas. The other man's ass grew as new muscles set in. Fur crept down from his back to cover his ass and then his tail. The fur along the tail sprouted long and thick and soon the red wolf tail was curled up and back against Greg's furry stomach. Thomas' long tongue panted from the effort of the transformation.

Greg felt his own tail set in. A tugging at his spine announced it but he paid it no mind as his plunged his thickening cock into Thomas. The knot at the base of his dick dipped into the other man's ass with every push. Greg's feet grew, placing him on his toes. The claws of his toes dug into the carpet for purchase.

Almost. A small voice said at the back of his head. Almostalmostalmostalmost...

Muscles lined Thomas' red furred body. The young man was yipping in pain as the change finished and pushing back harder and harder as he clawed the couch to shreds. With a final, hard push, Greg's knot rammed into Thomas' ass. Thomas came again, thick spurts of cum shooting from his own knotted wolf cock beneath him, covering the couch.

Greg growled in anger, grabbing Thomas' muscled furry shoulder, bearing down on him. With a renewed effort he slammed into the man over and over until, finally, his own release brought him nearly to his knees. He pulled his head back into a silent howl before biting down on Thomas' shoulder to feel the bones grind beneath his teeth.

He collapsed on top of the smaller man, black fur against red. His dick throbbed, still completely hard. Thomas pulled slightly but Greg's knot kept him in place. Greg growled tiredly in response. The young man twisted slightly to lick Greg's fur-tipped ears with his long tongue. In response, Greg reached around to grab Thomas' now eleven inch knotted dick. He pumped the dick in it's furry sheath slightly as he rubbed his head against Thomas' head.

Thomas whined in anticipation.