Sunny Shores was the simple, clean sort of place you'd go for a vacation. Hot, sandy beaches. Beautiful, green parks. And a lot of nothing to do except relax. It was a coastal, suburban town where time seemed to stand still. This was a good thing, if you were in fact on a vacation, seeking to relax. If you lived there, it was quite boring. In a town where the only thing you have a lot of is nothing, you have to find your own "something" with which to entertain yourself.
For eight-year-old Chip, that something was masturbating. Thanks to the internet, the pink half-bunny, half-skunk quickly mastered "the thing", as he called it. Of course, this didn't come out of nowhere. He was born a boy, but identified as a girl, acting as such. Worried, but supportive, his parents started treating him like one too. They bought him girl's clothes and his mom began taking him into public girl's restrooms, even if he was getting a bit old for the hand-holding. Sometime after all this, much to his embarrassment and confusion, Chip started getting erections in his panties. He'd suddenly feel a swelling between his legs as his penis pressed tightly up against the fabric, making him uncomfortable. He'd pull the bottom his skirt down between his legs, hoping no one could see. Chip's Dad gave him an awkward talk about "the birds and the bees", and a solution to his "stiffies" as Dad called them. That's when he learned how to masturbate. 
After the first time, it become more of a hobby than a quick fix to the occasional stiffy. With the help of the world wide web, he learned different ways to do it. Paws! Tail! Humping! He was in heaven. But his latest experiment would open up a whole new world, and not just for him.
"Yes, it's here!" Chip cheered, running to the door as he heard the tone of the doorbell.
"What's here?" asked Mackenzie, the little, mango, half-bunny, half-squirrel cub looking up from his cartoons as he sat on the floor.
"Um..." Chip trailed off, blushing as he opened the door. There was no way he could tell his four-year-old baby brother he bought a vibrator. "Just a new toy I bought off the internet."
"Here you go," said the delivery Dalmatian, handing him a small cardboard box. "Have a nice day."
"Ooo, can I play with it too?" Mackenzie asked, looking up at his big brother hopefully. He wagged his big, fluffy tail from side to side cheerfully.
Chip blushed deeply at the thought of that, feeling the pink pecker between his legs start to swell and push up against the soft, silky polkadots under his dress. "N-no!"
"Eh?.." The toddler whined. "Why not?!"
"B-Because it's a b-ig girl t-toy and y-you're not big or a g-girl, so there!" He quickly stuttered, stumbling over his words before running off, trying to conceal the tent in his dress.
Mackenzie crossed his arms and pouted, looking down at the floor. "I don't wanna play with your dumb toy anyway. It's probably for dummies..."

Chip escaped to the backyard, his barefeet squishing the grass between his toes as he walked over to the treehouse and climbed up its ladder. He breathed a sigh of relief as he plopped onto the mattress he'd hoisted up into the little clubhouse shortly after it's completion. Fluffy pillows. Fuzzy blankets. Dirty magazines. It was perfect.
The pink bunny blushed as he covered his face with his paws, hanging his head. 
"I can't believe I got a stiffy from THAT. What's wrong with me?" He said, his long, floppy ears hanging over his face like the strands of his long, purple hair.
He slowly lowered his paws so his eyes could see the cardboard box in his lap. He sighed again, and then figured he might as well open it. The half-skunk ripped off tape and pried open the box, smiling as he pulled out a cute, carrot shaped vibrator from the package. His cheeks turned cherry as he felt himself get hard again. He recovered fast.
Laying on his back, he looked up as he slipped of his polkadot panties, tossing them aside and pulling up his dress so it was out of the way. The pink bunny cub brushed the purple hair out of his face, and then opened the bottle of lube near his bed slathering it on the tip of the vibrator before slowly inserting the tip into his soft, tight tailhole.  He gasped out, grunting softly as the slick, orange round-point penetrated his butt, wetly sliding into his ass with a sticky "schlop". He pressed the button on the bottom and his pretty purple eyes grew wide as the faux carrot suddenly whirred to life! Every nerve in his lower body was firing off pulses of pleasure as it vibrated softly in his bum. 
"Unf, a-ah!" He moaned, reaching down and pushing it deeper and deeper, squirming against it as his rock-hard cock bobbed up and down on his belly.

Meanwhile, Mackenzie just finished watching his favorite show, and found himself very bored. Mom and Dad weren't home, so it was just him and Chip, but he was outside. The cub decided to follow him. He got up and journeyed to the backyard, dressed in just a diaper and a pair of striped socks. Once closer, he heard the noises coming from the treehouse and stared up at it curiously.
The half-squirrel carefully climbed up the ladder, making his way to the top, his heart beating faster and faster in his chest. From his point of view, it was like climbing a beanstalk to a giant's lair, especially with all the strange sounds coming from the clubhouse. He wondered if his brother was okay.When he finally reached the top and pulled himself inside, his bright blue eyes grew wide, his mouth hanging open as he stared at the strange sight of his older sibling sliding what appeared to be a carrot, in and out of his butt. Chip jumped and quickly sat up, as Mackenzie suddenly entered the treehouse.
"Mackenzie! W-What are you--?" He started.
"Why do you have a carrot in your butt?!" The four-year old asked.
Chip covered himself with his blankets. "None of your beeswax! Get out!"
"Ok, but I'm telling mom!" Mackenzie shouted, as more of a matter of fact, than a threat.
"No! Wait, stop!" Chip pleaded, stretching out his paw. "Don't tell mom!"
He didn't wanna have to explain himself to her.
"Why not?" Mackenzie asked, blinking as he stared flatly, straight at his brother.
"Um..." Chip tried to think of something, anything, until he remembered the erection-inducing thought from before. "...because I'll let you play with my new toy!"
"Really?!" Mackenzie squeaked.
Chip smirked. "Yeah, c'mere."
The mango-coloured bunny waddled over to his brother, plopping down next to him on the mattress, looking curiously at his sibling. Chip took a breath as he tugged the vibrator out of his butt and showed it to the toddler.
"This is it," He explained. "It's called a vibrator. You put it in your butt, and it shakes and it feels reeeaaaallyy good!"
Mackenzie made an ick-face, sticking his tongue out at the vibrator in disgust. "Ew, I'm not putting that in my butt! It's all wet, and it smells..."
Chip crossed his arms, one of his pink, floppy ears perking up as he raised an eyebrow and stared at his younger sibling in disbelief. "This coming from the kid who spends everyday -wearing- his potty."
Mackenzie blushed brightly. "T-That's different..."
"Just give it a try," Chip insisted.
"...Ok," Mackenzie replied.

Mackenzie got on all fours, facing away from his brother on the mattress. He blushed as Chip pulled his diaper down to his knees. His mango, floppy ears perked up as he heard the slick, sticky sounds of the lube being applied to the tip of the vibrator, and then he let out a little squeak as he suddenly felt it being pressed against his teensy tailhole.
"Ah, eee!" He squealed, his cheeks turning red as the round, smooth tip of the carrot plunged deep into his hole. He grunted, his ears standing at attention as it sunk deeper and deeper, until half of the toy filled his fuzzy, baby bottom. "Unh..."
The half-squirrel blushed as the little cockelet dangling between his legs poked out of his sheath. He'd gotten erections before, during diaper changes, but never like this. It was like his big brother had stuck a key inside of him--and turned him -on-.
The half-skunk giggled as he watched his baby brother's reactions. "Easy kiddo, I haven't even got to the fun part yet..."
Mackenzie wondered what could feel better than the tip poking and prodding the little boy-button in his butt, until he suddenly felt the device start to quake in his bottom. He quivered and squeaked, blushing harder as his brother slowly slid it back and forth, in and out of his bum.
"Unf! Ha-ah!" He gasped, panting softly as his sibling started to speed up steadily. 
Chip licked his lips, the paw that wasn't holding the vibrator on his own hard shaft, the bunny's pink face red with lewd bliss as he stroked his cock, listening to the sounds of his baby brother squeals and squeaks, squirming against the vibrator and his fingers, because of him! It gave him a rush like he never felt before, an amazing feeling of pleasure. He shivered with delight as his dick grew to a rock-firm four inches in his paw. He wanted to see Mackenzie's face. He HAD to. 
The mango-furred bunny blushed as Chip suddenly picked him up and turned him around, setting him in the eight-year-old's lap with the toddler's legs spread wide. Mackenzie's face lit up like a Christmas tree as his big brother continued to pound his butt with the buzzing vibrator, baby drool running out of the corner of his mouth, dripping from his chin.  Chip groaned at that cute, lust-lost face, pressing his forehead against his baby brother's as he panted and rubbed his wet, dripping cock against the toddler's butt--the four-year-old too dazed to care.
Mackenzie moaned, wrapping his arms around his sibling as he began bucking his hips up and down, rubbing his stiff little cocklet against his brother's belly instinctively. He churred, a sort of chattering purr, as ripples of ecstasy tickled his tiny body with unfamiliar sensations. He humped Chip's stomach faster and faster, harder and harder as Chip pushed and pulled the vibrator in and out of his butt, back and forth in his little ass until he suddenly felt a wave of unbearable pleasure wash over him, building up in his loins bursting out, overflowing. 
"A-ah!" He squeaked, hugging Chip tightly, making sounds no preschooler should make, as he came for the first time, all over his big brother's tummy, painting it with squirts of his hot, sticky, splattering spunk.
That set Chip over the edge. He humped his baby brother's butt, harder and faster, rubbing his cock between the toddler's fuzzy rumpcheeks. He hugged Mackenzie back, cuddling the little boy as he came for who knows what time, he'd lost count a long time ago--but this was definitely one of his bests. He murred as he shot ropes of wet, gooey spunk all over his baby brother's butt, coating  the toddler's fluffy, trailing tail in his thick cum.
The two collapsed, falling back onto the pillows of the treehouse mattress, covered in each other's cum. Mackenzie was laying ontop of Chip's chest as he breathed softly, his tail twitching between the older kid's legs. Chip panted, squinting as the world blurred around him, and took deep breaths as he tried to get it to come back into focus. For some time, the only sound in clubhouse was the whirr of the vibrator still in Mackenzie's butt. Just the "Bvvvvv!"
"Chip?" Mackenzie said.
"Yeah?" Chip asked.
"I love you," He happily replied.
"I love you too," The half-skunk said.
"Really?," The half-squirrel asked, giving his big brother as a soft, sweet smile. "You spent so much time alone in your room. I thought you didn't like me anymore..."
"Well, now you know why..." Chip joked.
The two giggled.
"But really, I love you Mackie!" He exclaimed. "I'm sorry for ignoring you. Between... this, and girl stuff I've just been so confused and exhausted."
"It's ok," Mackenzie reassured. "Being a girl is hard, huh?"
"...yeah," Chip said, staring up at the ceiling.
"...can I try?" Mackenzie asked.

Chip looked down at his baby brother and smirked.