"Just leave me alone!" Michael pleaded, clutching his backpack to his chest, but the three boys surrounding him didn't relent.
"What? Were just curious. Everyone knows hyena girls have dicks." The Doberman continued. "So what does a wimpy little bitch like you have between his legs? Do you have a teeny little cock, or an actual pussy? C'mon, just drop your panties and show us, and we'll leave you alone."
"I don't have a pussy!" the hyena boy protested.
"So your sister fucks your ass?" Tyler replied, and all three laughed loudly at the witticism.
They wouldn't have laughed, or even pestered the boy if they knew the aforementioned sister was around the corner, ear cocked and hearing every word. One of the reasons was that Becca was a senior. The other was that the tall hyena gave off a very distinct do-not-fuck-with-me vibe, one that her shy, bookish brother notably lacked. There was some truth to the fact that hyena males were notably less cocky than the females, and when a curious little Becca had peeped on their parent's doing it, it wasn't always daddy that was 'on top'. That didn't mean they had to take shit from guys like these three.
Becca knew she could just walk up to them and the bullies would scatter, but she also knew it wouldn't help her brother. His entire freshman year he would be the guy that hid behind his sister's skirt, and it would only get worse once Becca graduated. Fortunately, Becca had a creative, and very pervy mind. The ram and the lynx weren't a problem - they were just tagging along. If she put the loudmouth Doberman in his place, the problem would be solved. So she waited by the restrooms, biding her time. In less than a minute the bell rang and the group dispersed and the hyena slipped into the girls' bathroom, waiting just behind the door.
"You guys go ahead, I gotta take a leak." Tyler announced.
"Just hold it in, you're gonna be late for class."
"Pfft! Like I care!" he said, and Becca could almost hear him puffing his chest out. Too cool for school, huh?
Once she heard him go inside she slipped quietly into the boy's room, taking of her large studded belt. She wore a skirt, so the belt was just for show, but today she had a very practical use for it. As she expected, the stalls were all unoccupied and Tyler was at one of the urinals. She waited until the dobie was done, and while he was busy with his zipper the hyena jumped him. She grabbed one of his wrists and yanked his arm behind his back, pushing the protesting boy into one of the nearby stalls.
"Hey, what the fuck!?" Tyler growled as he struggled, only to wince as his hand was raised towards his shoulder blades and pain shot up his arm.
"Hello, Tyler. I don't think we've been introduced." Becca spoke, her voice as sweet as honey. Well, the sort of honey drizzled between a naked staked out body and a nest of fire ants. "I'm Becca, Michael's sister."
"So that twerp ran to his sister to tell her how we teased him?"
"Oh, no. That's between you boys, I wouldn't dream of interfering." Becca continued, grabbing the boy's other wrist and pulling it behind his back, easily overpowering the smaller male. "But I couldn't help overhearing how curious you were about what's between a hyena's legs." That made Tyler look behind him, and the sight of the hyena-girl's wide toothy grin made him flatten his ears against his head. He only became more afraid when the smirking amazon looped her belt around his wrists and bound them behind his back. With her standing behind him with that cartoon-villain smile on her muzzle, he was certain the hyena wasn't about to offer him pussy.
"If you try anything I'll scream!" he said, trying not to sound as afraid as he was, while Becca closed and locked the stall door.
"Ooh, I hope you do!" Becca crooned. "I'd always wanted to fuck in front of an audience, and I'm sure a lot of people in the school would love to see you scream as I take your cherry!" she said, and the expression on the dog's face told her the bluff had worked. Tyler was too stupid and too scared to realize that if they were caught, Becca would be in a lot more trouble. But freshmen were so worried about their reputation, and he knew he'd have to spend four years as the guy who'd screamed while a girl fucked him in the ass. He didn't say anything and tried his best to look unintimidated, but the hyena could read him like a book. She had him!
"Good girl!" she said, pushing his shoulders down until his head was resting on the toilet seat. Reaching around his waist, she unbuckled his belt and slid his pants and boxers around his legs in one smooth motion. She took a few seconds to admire the sight in front of her - the fourteen year old dobie bent over, hands bound, pants around his ankles and his supple young ass on full display. She'd removed her panties before coming in and she could feel her pseudo-cock emerge and rub against the fabric of her skirt.
Fortunately for Tyler, the sight of that black and brown butt was getting Becca pretty wet. She slid a couple of fingers inside her pussy, pumping them for a few seconds until they were nice and slick. She spread the Doberman's cheek with one hand and quickly proceeded to penetrate the kid with both lubed digits. The bound boy grit his teeth and tried to squirm away from Becca's grip.
"Calm down, puppy! Believe me, you'll want some stretching before I fuck you..." she spoke softly to her victim while she pumped her fingers in and out of his virgin hole. "Or maybe I'm reading this wrong? Maybe you're so eager for my shaft that all this foreplay is frustrating you?" she teased as her fingers curled up and found his little boy-button, making the canine whine through clenched teeth.
"Ooh, so that's it? Puppy wants a bone? Well then..." she said, grinning as she withdrew her fingers and admired the stretched and slicked hole. She tucked the front of her skirt into her waistband and took a firm hold of the boy's hips, letting her tip press against that primed pucker. She pushed as the dobie whined, and once she felt the blunt tip slip in she gave one savage buck and sheathed herself in the pup's warm depth's, filling him with eight hard inches of hyena meat. She grunted as she felt his ring twitch and squeeze around her massive clit and came just from the sensation of the boy's ass fighting her. Still, unlike a male, she could keep going. She scooped up some of her honey and drizzled it over the pup's stretched pucker.
This wasn't Becca's first taste of boy ass. A few years ago she'd dated Rudy, a feminine bunny-boy who loved having her top him. Even though he was bi and had anal before, Becca could never bring herself to really rail the delicate rabbit, so she'd always been gentle and loving with him. She also never needed to help him with bullies. At first the jerks at school had picked on him for being a 'fag', but had underestimated how popular the twink was with the girls. Once they realized bullying him would mean spending their Saturdays dateless, they quickly stopped.
So when Becca started to thrust into Tyler's violated ass, she was neither gentle nor loving. She pounded her captive bitch, the smacks of her hips on his cheeks echoing against the tiles as the hyena girl let out her wild side. To his credit Tyler never actually screamed out, no doubt terrified of somebody coming in and catching him get pegged. Becca put her hands on the boy's ass, kneading the cheeks roughly as her shaft violated the Doberman's no longer virgin pucker.
"Mhh, doing great, bitch! Are you sure this is your first time?" she spoke softly, grinning when the dobie flattened his ears in shame. "Ungh, you're a natural! If you keep this up I just might have to put a leash on you and keep you as my personal fuck-hole!" she said with sadistic grin, aware she was enjoying this way, way too much.
She grunted as she humped her doggy, the boy panting while his whole body shook from the hyena's onslaught. Unsatisfied with his level of involvement, Becca gave his ass a good slap. She moaned as this made his pucker tighten even more around her, and soon she was giving his ass a spank every time she bottomed out, making it grip her pseudo-cock as she slid out and the bathroom ring out with each smack. While she was admiring the way the teen's ass jiggled with every slap, Becca caught sight of something else dangling beneath the trapped boy. Instead of delivering another smack to the kid's rosy cheek, her hand darted between his legs and gripped a very erect canine cock.
"Ooh, what's this? You little slut! Rock hard without even being touched..." she teased Tyler, the boy moaning as she held his shaft. "Is this why you've been asking boys to show you what's in their pants? Just hoping one of them would bend you over and give you what you need? You must be so grateful to finally have someone pounding your slutty ass. Now say 'Thank you'." She said, giving the dobie's cock a good squeeze when he failed to do so immediately.
"Aaah! T-thank you!" Tyler squealed out, his blush visible even under his fur.
"There's a good bitch!" Becca said, letting go of the boy's cock and smiling even wider at the relieved yet needy whine that escaped his throat. She didn't really think Tyler was gay, but her time with Rudy had taught her how to hit that spot inside a guy's ass. And nobody was straight enough to stay limp with a girl as skilled and sexy as I am pounding his prostate. 
Both hers and Tyler's ears perked up at the sound of the bathroom door opening and somebody walking in. The dobie's eyes were wide with terror and he stood silent and still as the sound of footsteps echoed in the suddenly quiet boy's room. Becca sure as hell didn't want to be discovered, but couldn't resist giving her bitch a little scare. She ground her hips into his ass, the terrified boy putting a hand on his muzzle to keep from making any noise while the hyena's shaft prodded his insides. They heard a zipper and soon after that the sound of someone using the urinal. Becca smiled as she started to give short, sharp bucks while her victim struggled not to make any noise. After what seemed like an eternity, the mystery person left and Tyler started to take deep, ragged breaths as the terror of being caught passed.
While it was fun to watch him squirm, the slower pace had frustrated Becca. However, she knew just whom to take those frustrations out on. She grabbed the boy's waist and once again began to pound him mercilessly, her spotted hips a blur as she bred her bitch. Tyler was caught off-guard by the assault and almost screamed when Becca began nailing him, but caught himself in time. He closed his eyes and bit his lip, hoping the hyena would finish soon. Becca grunted and panted, letting go completely and fucking her bitch with a feral intensity. She regretted the boy had been docked, having always wanted to grab someone's tail and drag their ass back to meet each thrust. Instead, she decided to improvise, and grabbed the doggy by the scruff of his neck, pulling his head up while she abused his rear. She was really getting off on this, dominating someone so completely and letting go of all her restraint, and knew just what it would take to push her over the edge. She slid her other hand between the pup's legs, grabbing his fully inflated knot.
"Mrr, c'mon bitch, cum for your alpha!" she husked, giving a low growl as she started to rhythmically squeeze the dobie's knot. That was more than Tyler could take, and his shaft started to twitch and spurt doggie cum all over the tiles. Becca's paw moved to the tip of the gushing cock, and she soon had a handful of puppy-juice. She brought the cupped hand to Tyler's head and smeared his cum all over his muzzle. The sight of the panting pup's face covered in his own jizz combined with his pucker clenching around her clit pushed her over the edge, and she gave one last sharp buck as her pussy gushed, adding to the mess on the floor.
Getting her breath back, she pulled out of the dobie, admiring his now gaping ass as his knees buckled and he was left kneeling, bent over the toilet bowl while his body still twitched. A perfect position for what Becca had in mind. She spread her legs and positioned herself so her pussy was over the boy's ass, holding his bound arms as she relaxed and emptied her bladder over her captive. Tyler mewled and tried to struggle but after the brutal fucking he was still too weak to stop the hyena from marking him like a bitch.
"Now, the way I see it..." Becca said once she was finished, loosening the belt and releasing the Doberman. "...everyone's still in class, so if you're quick and careful you should be able to get to the showers and manage to wash most of the mess off before next period. Or you could walk around like that and let everyone know someone marked you. Either way I'm good - got mine!" she gloated cheerfully, giving the hot-mess bully one last glance before unlocking the stall door.
"See you 'round, lover!" she quipped before walking away like nothing happened.
*******
"You didn't!" Stacey said in disbelief, cheeks flushed as she snuggled against her girlfriend.
"Swear to God! From what I heard later, he never bullied anyone after that, and he was never late for class again!" Becca said, both girls giggling at the thought. "All right, now it's your turn. And remember the deal - something really messed up that you've never told anyone before."
"Well... " Stacey spoke, looking away from Becca and blushing as she did "... for some time now I've had these fantasies about what it would be like if my little brother was actually my sister...".