Down the block a few minutes away was a 15 yr old boy named Preston. Tonight was his birthday he was turning 16, but his parents had pre planned his party to be on Saturday, it was Wednesday, so he couldn’t wait! It was far better to be with friends he thought. Birthdays alone just feel like any other day. Video games, chores, sleep, and taking care of his puppy Toby. His parents gave him Toby as a very young puppy (just weened) at Christmas. Toby thought it was a kind of messed up gift because his dad told him he was actually given the gift of responsibility. So really just more chores, but in the next few days he began to really really love this dog. At first the pup slept on Preston’s chest, as he grew He slept in Preston’s bed next to him, they were like best friends, the only real friend Preston had, the only one who was always happy to see him. They cuddled and often snuggled together in the mornings, Preston began to feel like the extra chores, walking and feeding Toby weren’t so hard after all they were all ease compared to what he had gained, everytime he took him outside it was another chance for him to play fetch or run together, as Toby grew Preston had begun playing a game where he would run from Toby as Toby followed him and Toby would eventually catch up and pounce on him. It never hurt bad and Toby would end up licking all over Preston’s face which always made him giggle. Since Toby had passed the 6 month mark he had starting humping things which wasn’t really a problem Preston assured his parents, because he had never wanted Toby fixed. He hated the idea of hurting an animals privates, and thought all the reasons people did it was rubbish. It had become a slight problem though. And it bothered people Preston’s mom told him. So everytime then after when Preston would pull Toby off of furniture legs, sofas, pillows, rarely people even. and take him to his room, where he allowed Toby to hump on his beanbag chair which was really soft. Only now There was such a stain on one side that Preston couldn’t get off, he had to turn his beanbag chair around. Admittedly he always thought it had been hot watching Toby fuck his chair, he even played with himself watching a few times, he admired the short glimpses of his best friends doggy cock occasionally getting to see it spurt some liquid. Toby had always been a very sheltered child from religious parents, he always had to find everything out on his own, no one told him anything besides the internet, and his body, which was stunted from the lack of stimulation , information, and his inability to have a girlfriend he could tell his mom about or even be around outside of school because she told him he wasn’t allowed to date until he was 18. He hated not being like his friends, but he had plenty of fun alone, even more so with Toby around. This was the hottest thing he had ever been able to see. Toby was about 9 months old in the present, and their relationship only grew closer, they never did anything sexual together, Preston only watched, the thought never crossed his mind. Preston was playing call of duty when his mom yelled at him to take the dog out, I turn 16 in just a few hours he thought to himself, feeling excitement quiver down his spine. I don’t feel any older, tho he laughed. He put down the controller and grabbed Tony’s leash off the wall, Tony instinctively leaped down off the bed and happily let Preston clip it on him. As they went outside the sun was just setting and it was golden hour. Preston thought to himself watching Toby sniff through some grass at the nearby park, “I wonder what being a dog is like, they never really worry about people liking them, or having to fit in, or school, school work, work in general, they always played, usually happy”, and Toby in particular was a very gentle dog. eh fun thought he said to the wind, as he backed away to return home after Toby was done doing his business, he had to stop suddenly to not bump into a very beutiful blonde female, Olivia from school, walking her full blooded white poodle, Toby was a Great Dane mix with boxer-lab and he was truly beautiful but not pure breed unfortunately. hey sorry he said as he almost ran into her, she laughed and responded with “oh it’s fine” kind of curtly but she continued to stand in front of him like she wanted the conversation to continue. He was nervous, “nice day out isn’t it” “yes I totally love this weather” she responded. good, he thought she likes me enough to talk to me, they began a conversation about last years science class and the fair team they had been on together when Toby catching the attention of Olivia’s poodle who had already been infected by another dog in the park at this point, and smelling her heat walked his horny self to her backend and began to sniff her snatch, and lick on her cunt, Preston didn’t notice till Toby attempted to mount his first bitch failing miserably as Preston pulled his leash away hard, falling to the ground, Preston apologizes to his pretty friend, “ dear god I’m so sorry, he’s crazy, we need to get him fixed” as she was telling him it’s fine it’s a body function, they need to get it out too sometimes ya know, and winked at him. He was so turned on by this he began to feel his underwear tighten and he got nervous, he smiled and said “well it looks like it’s starting to get late, I better head back now” even though they made it back home before the sun completely set. Preston laid back in his beanbag chair and began playing his game again, the sweet menonry of his recent encounter giving him an estatic bliss, Toby of course began humping his chair, and being to close to him, annoyed Preston so he tried to push him off to quit but actually got hit with a tiny amount of dog pre on his wrist, “ew gross” he exclaimed even though he was beginning to get rock hard just from this experience. He almost licked it off his hand but thinking better of this he put it on his balls until it dried and began playing with himself incredibly turned on as Toby once again resumed his session with the chair, Preston watched in pure awe, arousal, and fascination at the spectacle in front of him, never have been this close to seeing his dog best friend get off, and just as his puppy began panting Preston began to feel the first few waves of his orgasm coming on and funny enough could sense Toby was close as well. Just as Toby placed his final humps before ejaculating himself all over the side of the beanbag and carpet, Preston finished along with him at the same time, squirting all up on his chest and neck area, surprised he shot so far he looked at the dog is disbelief, to which he seen the dog happily panting. Preston didn’t feel one ounce of shame. Partly because this was his dog and best friend, and he had seen similar stuff and had fun to it many times before. And partly because the thought of touching Toby of anything real of that sort was so foreign to Preston’s mind he never considered it. As Preston got up to go to his bathroom to clean his cum off of him and go pee, he itched his balls which were sprouting a small thin layer of blonde fur apart his shaved jewels, he had pubic hair but it’s funny because he shaves it off always and it never feels like this he thought to himself, not knowing that was where he had placed his now infected dogs seed. Preston hopped in the shower because the toilet paper kept sticking to him, but left the door open. In the shower Preston played with his foreskin, thinking it felt longer than usual and worried something was off? He figured it was just because of his recent masterbation session and chopped it all up to that. Funny enough he loved the feeling of stretching and playing with his unknown new growth. He was unbelievable horny still and he never usually was at least for a while right after he was done and found that unusual, his balls felt full, and firm. Even tight, he squeezed them and felt unbelievable pleasure, making his dick rise. He began to wash himself and never noticed that his dick never went down because it attached itself to his lower belly, he figured he was just still hard, which he was, but something else was going on. As Preston turned the shower off the cold touching his naked body was enough to send a shiver through him, and then an immense wave of pleasure, at the peak of which a ton of precum dribbled out of Preston’s erect penis, and splattered to the bottom of the tub making little drip and splat noises. While he tiptoed side to side with pleasure on his tippy toes, A loud moan escaped his lips before he caught himself and covered his mouth and waited to see if his parents had heard or not. Scared actually frightened of this pleasure Preston stepped out of the shower in front of the mirror and toilet and looked down in amazement rather than the expected horror anyone else would’ve had. That he had a full canine sheath where his dick was, pinching himself to see that he wasn’t dreaming he examined closer, and noticed little hairs the color of Toby’s sheaths fur all over his now large-covering foreskin. He shouldve been shocked, terrified, even aghast, but he was so turned on by all of this his now bright red canine pecker extended out of its sheath, and dribbles more precum into the toilet this time and on Preston’s growing new fur, ripples of pleasure ripped Preston as he stood there attempting to get his breath once they subsided he let himself get soft and back in his new sheathe by breathing deeply, he peed again and went to bed. Not noticing he was changing more with each wave of pleasure, his lower back now sprouting dark fur like Toby’s. He layed in bed planning to not tell anyone because this was the most sexuallly exiting thing that had happened to him ever, 1 and he didn’t want the family to know he did stuff with the dog 2 thinking whatever this was must’ve only spread that way. He dosed off with his music playing with Toby beside him, Toby content that his masters change was coming along well, he fell asleep with his head resting on Preston his best friend, they were becoming closer than they had ever been.
As Preston dreamed he dreamed him and Toby were running across a field together playing fetch, the entire field was mown nicely, but you couldn’t really see any background apart from trees. Preston was running and smiling and running and laughing, until while Tony chased Preston Toby pounced on him with a thump. It didn’t hurt but slightly knocked the wind out of him he noticed Toby feeling heavier now than before, like a huge weight and he couldn’t get him off, he felt a huge warm rod hanging pressed to his taint and knew immediately what that was, slick and sticky throbbing up and down and for the first time ever he knew now what it wanted, his virgin asshole feeling heat as blood rushed to it with this new realization, getting so turned on he felt like he was blushing uncontrollably. Immediately noticed he was already hard as a rock. But he was totally back to human in this dream. He felt the canine cock rhythmically flex every second or so and it begin to spurt doggy precum all over his taint and balls, he was so turned in by this but he needed it inside him! While simultaneously thinking “how weird”? no matter the angle though, it would not go in, his stimulus to the pup however caused dream Toby’s orgasm as he pumped hot seed all over Preston’s asscrack and completely covering his taint and balls. He awoke just as he felt hit streams of jizz erupt in his underwear his new canine dick hard in its sheath, oh oh ooooh Preston moaned as he watched hair grow on his arms and face in rhythm with each squirt. His lower back hurt bad, and as his climax ended he laid panting like a dog he reached back to feel a very real tail with blonde hairs on it! Massively turned on by this again not even having time to go soft, Preston put his furry hands into his britches, feeling his new cock made him so estatic, he loved the edges and how he could feel inside the sheathe it was so much more sensitive too! Curiously he cupped the base of his dick and to his surprise he thought he had sprouted an extra pair of nuts! He quickly grabs his phone and looks up dog anatomy and find out they are called the knot, it’s a pleasure muscle that keeps the dogs cum from falling out of the female before impregnation. never having heard about this before or even knowing its function barely even knowing what sex is apart from wet dreams( including the one he just experienced) he just shrugs it off as a handle that might help him pee later. Feeling all the cum in his undies Preston remembers his dream and looks back to see Tony spooning him, but the bed was still very dry and Tony slept like this often with Preston. What a wild dream. Little did he know it was due to the virus changing him slowly but surely as Preston’s immune system was stronger than most. Preston remembered he is 16 now! What a cool present he thought! It’s like a superpower kind of! Me changing. The pleasure. The fun, he remembers his dad telling him weeks ago he was going out of town for work the day of Preston’s birthday, but that he would be back by Saturday the day of his party. His mom was out shopping til late with his younger brother Sam, who was 14. He couldn’t expect them till then. Having this thought he noticed a growing sensation in his loins, it felt warm and his bulge got noticeably bigger and his dick once again filled with blood swelling up and beginning to poke out of the sheath, preston panted and tore his cum soaked undies from him, as his new doggy cock spring to life in front of him, fully extending 8" to the knot which was a sizable 3” but still in his sheath uncomfortably twitching. With his hands on his upper thighs he panted watching the precum drool off the now pointy tip onto the carpet below absolutely surprised. He was worried if he got much worse, he would have to tell his parents for fear of being like this forever. And not being able to hide it. Able to catch his breath for a second Preston noticed Toby had gotten down off the bed and was looking at him all concerned. Feeling the familiar pressure brew below, and the familiar chills come up the bottom of his buttocks, spine and ballsack Preston thrusted his hips backwards a few times as he moaned and cried from the waves of bliss that hit him in an instant, causing him to stretch out and shoot another small load across the floor below, hands free, it felt like the intense sexual tension was caused by his body’s attempts to fight whatever this was. And not succeeding. Toby went right to his masters seed and sniffing licked it right up, immediately stared Preston down as Preston stared back with shame worry fear and lust. Noticing his best friends doggy dick was erect and slowly poking its head out of its sheath. He realized he could be his mate for the first time ever he had this thought, and this thought made him feel dizzy, with pleasure, his best friend, his mate! his infected mind would have it no other way! He began to approach Toby and Toby stepped forward sitting down exposing himself entirely, his huge canine cock pulsing and growing with every pant of the beautiful pup, wondering if it also pulsed with his heartbeat Preston reached his right hand out to touch the base of the sheath, causing Toby’s lipstick to come fully out knott and all, Preston squeezed the knot, and was rewarded with Toby shuffling his feet and whining in pleasure, this turned Toby on even more, he noticed the hair creeping thicker and thicker all over him with each second, almost fully anthropomorphic at this point, halfway through his transition, and placed Toby’s meat in his mouth, surprised at how big it was but not scared like he would’ve been had he been himself, he wanted it all no matter how big now! He realized he could feel his heartbeat, And engorged himself on the dogs penis until his pup stood up, taking the hint, with his face now fully doglike because of the seed he just took in, he wipes his mouth and re adjusts his rump like the dream he just had. Too late now for any going back he thought! As his canine best friend licks over his virgin asshole with passion. He instinctively raises his rump to match the licks, each time Toby slithing deeper and deeper into his man-cunt eliciting loud moans from the 16 yr old real life furry!
Preston was feeling so good, A small puddle of precum on the floor beneath him already felt his new-mate mount on top of him for the first time, it was so romantic, so sensual, so animal. It was bliss. Preston knew he had to fully let go into these desires, he had no option, he was loving every second! He raised his rump to meet its target and as Toby felt the tight anal ring around the tip of his sheath and boner, it slid right in from all Toby’s pre easily.
And immediately the boxer mix jutted his full dick out of his sheath into the changing boy and began fucking him rapidly. Eyes immediately wide Preston knew what he had gotten himself into as the beautiful dog fucked him from above, when his full dick ejected from the sheath it caused Preston’s too as well as cause it to jut a bit of sperm. screaming in a mixture of pleasure and pain his spine cracked and bucked while they were fucking and became dog-like furry hands became paws, and hind legs emerged from the bends, his tail stretched out to its full length in between the two mates. he fully relaxed and his new canine mind let him take more of his lovers cock! Fickijg now in pure pleasure he turned his doggy head upward to meet his mates with a small howl of pleasure and nuzzled deep into the mane of his fur. Cumming profusely onto the floor and his mate causing him to drip heavily from behind he felt Toby’s knot, the last of his human mind warning him to brace himself, he came huge as the Shep-boxer pushed his knot all the way in the dog-boy. Heaving it deep Toby locked in and licked his mates cheek like he had done so many times when they used to play together. He turns butt to butt with the panting Preston who was finishing his transformation, and continues to lick him till Preston falls on his side as he is pumped full of seed his change finishes rapidly, causing loud moans and spasms, and more cum from the new pup to splatter all over the ground. He fights it a little but knows it no use and finally while cumming his last becomes a copy of Toby, a twin. And a mate, probably for life. In love with his new lover they nuzzle and cuddle until the knot pops out with a swuishhhhhh of fluids dripping causing Preston to lower his tail like he was a female peeing. Toby cleans up his mess on Preston’s pretty anal ring, and they fall asleep.