The Buizel was out on the river in a small Kayak made for smaller Pokemon. He wanted a day to get away from school, but he didn't want to go alone. Before he left the house in his Kayak, he had the family pet, a Rockruff follow him. The Buizel's intentions weren't completely pure, he'd honestly been in something of a dry spell, and so whenever he couldn't get a hook up, the Rockruff always made a good little hole. The Buizel went into the Kayak and had the Rockruff sit on his lap, he then used one side of his oar to push them off the bank and into the midst of the river where he'd start rowing them down away from the riverside home. 
The Rockruff sat in the Buizel's lap happily, curling up and letting the sun warm up his fur. Of course, this had been something of a pattern for the two, so the canine had a pretty good idea of what would be happening soonish, and he was honestly pretty excited about it, his tail wagging pretty fast. The Buizel smiled down at his little pet and said, "I hope you're excited little guy, we'll be together all day.''The Rockruff barked an excited response, happy as could be.
It was several hours later and The Buizel and Rockruff were pulling into a popular stopping spot of Pokemon on the Weekends. Luckily, this place would be completely deserted today. The pair got off their Kayak and started pulling it up onto the shore. As they were walking, up onto the bank, the Buizel was practically exploding with sexual tension. It had been a month since he'd seen action, and he was about to give a whole month of pent up need into his cute little pet.
They reached the clearing and the Buizel brought out a blanket he'd hidden there in the grass last time he brought Rockruff here. He laid it out on the ground, making sure it was extra soft for his little buddy. "Come on over to the soft patch of grass, Rockruff," the Buizel said, patting the blanket.
The Rockruff complied happily and waddled over to the blanket, then lied down on it's back.
"I hope you're ready, pup, this isn't going to be easy. Just try and bare with me, okay?" The Buizel's cock was already fully grown out of his sheath, the knot having already formed, he was as hard as he could possibly get. Seeing his pet on his back, he couldn't hold back. He got on all fours over the little dog and aligned his member with the other's little hole. With one hard thrust, he rammed it into the core. The Rockruff yelped in pain as the Buizel's member tore through his poor pet Rockruff's ass. The canine's eyes watered, but he just gritted his teeth and accepted it.
"I know, I know, just.. Please stay with me, I need this so bad little guy, just hold on" the Buizel said, commending the little Rockruff before he began thrusting in and out.
Rockruff didn't answer back, he just bit into the blanket to try and stop himself from screaming.
The Buizel began thrusting in and out, picking up speed as he did so. Rockruffs' paws were digging into the blanket as he was jolted back and forth with the rough penetration. The Buizel's heavy ball sack was slapping against the other's pet's taint as he went in for the deep penetration.
The pain was almost unbearable for the Rockruff, but he had no choice but to hold on.
The Buizel put more of his weight onto the small critter, starting to absolutely rail his little bottom as the Rockruff's yelps became constant.
The Buizel continued on, wanting to release as soon as possible. He knew it would be best for his pet if he could release, but he couldn't last much longer after a month of pent up frustration.

"F-fuck, good boy.. Get ready Rockruff, you're gonna need to bite down on the blanket.." The Buizel howled in pleasure as he slammed his hips forwards a last time and knotted his poor pet.

The Rockruff cried out in pain as he felt the other's knot expand inside him, blocking his insides completely. He grit his teeth and bit down on the blanket, stopping himself from screaming as he breathed heavily through his nose. He just hoped the pain would be over with soon.
It was a good minute before the Buizel finally started to calm down, but even then he stayed knotted inside the little dog, not wanting to move at all.
The Buizel finally after holding it back starts cumming inside his poor pet. He moans out loudly as he holds the Rockruff's hips tightly and unloads inside him. The little canine's ears are laid back as he tries to keep quiet, breathing through his nose as he arches his back and tries to escape from the painful knot locking him down.
The Buizel's knot swells up inside the little dog's taint before shrinking a bit, but still keeping him locked down tight.
"F-fuck.. Goodboy, Rockruff.." The buizel huffs out, he feeling so much better now that he was able to get laid. He'd never gone that hard with his pet before, but he was too distracted by his afterglow to care all that much.
The Buizel pulled his hips back a bit, the knot slipping out of the little dog's taint as he pulled out completely. He panted hard as his member started to soften before he looked over at his little buddy.
The Rockruff was in a much worse condition, with blood dripping down his legs as his own member had popped up from the rough penetration.
The Buizel smirks, unable to help himself as he saw his poor mutt slut all fucked up. Aiming his cock down at the poor little Rockruff, the Buizel started pissing all over his pet.
The Rockruff whimpers, but lays there and let's his owner mark him. The yellow liquid stains his fur and soaks him completely as the Buizel just continues to let it flow.
He finishes up, and the Rockruff slowly gets up, starting to walk off to find a place to clean himself.
"Ah, where are you going? We're not done here." The Buizel said, stopping his pet from walking away.
"Open your muzzle, you still have to clean me off." The Buizel pokes the Rockruff in the nose with his musky cock.
The Rockruff looks up at his master with a deadpan expression. He doesn't say anything, but he gives a quick nod as he opens his muzzle and leans in, giving the head of his owner's member a quick lick.
"Hahaha, more enthusiasm!" The Buizel slaps his pet on the head, before leaning down and pushing it deep into the Rockruff's mouth.
The Rockruff lets out a gurgle as the thick beast meat is stuffed into his throat, the head pushing down his throat. He starts to choke and gag on it, tears welling in his eyes as he sloppily slurps and licks at his master's meat, trying to keep quiet.
The Buizel moans out as his pet tries his best to please him.
Panting heavily, the weasel pushes the Rockruff all the down on his cock, the pet's nose scrunched up against Buizel's smelly crotchfur.
"Keep licking, you little freak." The weasel grunts out, enjoying how pathetic the Rockruff looks with his muzzle completely filled with meat.
The Buizel lets the Rockruff lick his member for a good while, before he starts pushing it in and out of the pet's face. He goes slow at first, but then quickly begins to pick up speed as he begins to get more excited.
"Nyaah! Good boy, keep going!" He pushes it in and out of the Rockruff's muzzle, that familiar wheezing sound filling the air as his pet starts to choke a bit.
The Rockruff tries his best to please his master with his mouth, gurgling around the thick member as tears run down his face.
It doesn't take long before the Buizel is just roughly facefucking his pet, that long beast meat deeply shoved down the pet's throat as he holds it in place. The weasel starts to moan loudly, as his pet's watering eyes and gasps for breath just make this all the more hotter for him.
"Oh yeah, oh f-fucking yeah, take it! Take it like a good boy!" He grunts out, holding his stiff member deep in the Rockruff's muzzle as he starts to furiously knead at the pet's side with his thick claws.
"G-good boy! Take it! Take it like a good doggie!" The Buizel moans out, holding his hips still as he starts to spray his warm seed into the back of the Rockruff's throat.
The weasel grunts and groans as his thick member starts to pulsate and pump more and more hot sticky seed into the pet's mouth.
The Rockruff gurgles and chokes on his owner's thick meat, some of the hot sticky liquid managing to leak out from the corners of his mouth. The weasel doesn't let up though, and continues to thrust his hips forward, more and more of his seed spurting out.
The two stay like that for a moment, the Buizel moaning as he lets his climax finish itself off. He slowly pulls out, a little bit of his seed leaking down the pet's mouth and running down his chin.
"Good boy, ahhhh.." He pets the Rockruff's head, the little dog choking a few times and taking several deep breaths. 
The Buizel laughs at his pet struggling. "Well, I got what I wanted," the Buizel says as he starts walking over to the Kayak.
The Rockruff stays on all fours, coughing and gagging on his owner's seed for a moment, before slowly standing up. He starts walking over to his master, his head looking up at the setting sun. Dusk was setting over the river, and then something sparked in the Rockruff. The Rockruff was enveloped in a dense white light and moments later he evolved into a Lycanroc, now he was significantly bigger than the Buizel, yet the Buizel hadn't even noticed yet, he was busy packing up the Kayak.
The Lycanroc had a mixture of feelings at that moment. He wanted to immediately attack and rip the weasel's throat out for what he did, but he also knew that his master loved him and that he just really needed him.
"Are you ready to go, Roc-?" The Buizel gasps as he turns around, finally noticing the large beast that had now been staring at him for who knows how long.
The Buizel squeaks and falls back onto his ass, crawling backwards slowly out of shock. "W-w-what the hell?! How did you...you're a Lycanroc!" He stands up and starts walking backwards towards the Kayak, his eyes darting between his Lycanroc and his Kayak.
The Lycanroc's ears flick as he stares at his master. The only sounds that are made are the chirping of insects and the gentle lapping of the river.
The Buizel drops to all fours and bows to the Lycanroc, "I'm so sorry, please don't kill me. I just really needed to get off.."
The Lycanroc doesn't move, as the Buizel starts to panic again. "Please, just give me another chance! I'll never do it again!"
The Lycanroc breathes in deeply, and makes a short growl. The Lycanroc slowly stalks towards the Buizel, his master freezing in fear. He gets nose to nose with his master, growling at him before shoving the Buizel back onto his back. Buizel would look up at the Lycanroc and squeal as he saw his pet smirking at him with a lifted leg, the canine packing a huge knotted cock, about half the size of the Buizel's body. "W-wait, t-that's.." The Buizel gulps.
The canine grunts, and smirks at the Buizel as if to say "Oh yes, you'll take every inch of this." The Lycanroc grins as he starts to push his cockhead into the Buizel.
The Buizel screams in pain as the Lycanroc's shaft pushes into his hole, ripping him apart at his entrance. The Lycanroc lets out a satisfied growl as he pushes his whole length into the Buizel, the Lycanroc's knot resting on the pup's ass, ready to be slammed in to break the Buizel.
The Buizel screams in agony, his eyes start to water as he grips fistfuls of sand and dirt. He looks up at the Lycanroc with tears streaming down his face. The Lycanroc just snarls down at him, not showing any sympathy. He leans down and bites down on the scruff of the Buizel's neck, forcing the Buizel into submission. The Buizel yelps in pain as his master shows him who is boss.
The Lycanroc pulls his hips back, dragging his knot slightly off the Buizel's rump. The Lycanroc only manages two slow shallow thrusts into the Buizel before he rams his knot in hard, smashing into the poor canine's hole.
Blood sprays out of the Buizel's ass, several loud snaps being heard as the knot popped into the Buizel. The Buizel's screams are muffled by the sand as he bit into it in pain, his paws scrabbling against the earth.
The Lycanroc starts to furiously slam into the Buizel, his knot slamming in and out of the Buizel's hole. The sounds of flesh being pounded and ripped apart fill the air as the wet slaps of their crotch and ass smashing together echoes across the river.
The Lycanroc grunts as he starts to push harder and faster, the wet sounds of his knot dragging against the Buizel's hole fills the air. The Buizel starts to whine as he tries not to move an inch.
The Lycanroc manages one last powerful lunge as he holds his knot in deep, ripping the sphincter apart and causing a spray of blood to splash onto the ground. The Buizel screams out as his insides get torn up, the knot smashing into his bladder and intestines.
The Lycanroc snarls in pleasure as he holds his knot in deep, filling the Buizel's hole with his hot canine seed. The hot liquid sprays against the inside of the Buizel's guts, filling him up and causing him to bloat up a bit.
The Lycanroc finally pulls out of the Buizel, his bloody red member dragging out of the hole leaving a deep red trail. The Buizel coughs up some blood, before his eyes roll in the back of his head and he falls into unconsciousness.

Sighing from pleasure, the Lycanroc looked down as his pathetic master, pondering on what to do. After a deep exhale, he decided that he wouldn't leave his master to die. That said, he did have one more part of his revenge. Lifting his leg, the Lycanroc starts to let out a huge wave off piss over his new bitch, marking him as his. He watches as the stream of yellow washes over the unconscious canine, seemingly drowning him in the liquid.
After a few minutes, the Lycanroc stops, and takes a deep breath. He stares at his master's prone form, wondering if he had gone too far. He looks down at the pathetic, bleeding Buizel with a smirk. He was happy that he got revenge, the Buizel deserved it. Now he picks the Buizel up by the scruff of the neck and runs him back home. Whether or not his master survived or not, the Lycanroc didn't much mind. The thought of being able to rail his master like that again, though? Made him run just a little bit faster than he would have otherwise.