Inky tossed a cold beer can to his cousin Jim as he returned from the kitchen, flopping back into his deckchair in the back yard. With summer ending and the trees turning brown it wouldn't be warm enough to hang around outside much longer – which was all the more reason for the rabbits to enjoy themselves while they still could.

"Thanks," Jim said as he snatched the can and popped it open, casting a glance at the three girls who were sitting together and gossiping. Whereas Inky and his sister Cheeky had purple fur with white undersides, Cheeky having a bit of black on her upper body, the other three had far more unusual patterns with clear dividing lines running down their bodies: Jim was black and pink with a gray front, his sister Jam's fur was cream and pink with a black front, and Inky's sister Bun was orange and black.

Inky leaned back into his chair, opening his beer can and taking a sip as he stared absently off at a nearby tree. His long rabbit ears perked up as he listened in on what his sisters and cousin were talking about:

"...you two are so much bigger than I am. It's totally not fair!" Cheeky complained, and Inky raised an eyebrow, glancing over in time to see Cheeky cupping her B-cup tits, held in a bikini top.

"We're not THAT much bigger," Jam insisted, gesturing towards her D-cups. She then glanced over at Bun's cleavage, which was bigger and rounder still. "Okay, well, maybe a little."

Bun gave a little chuckle and sipped from the drink she was holding in one hand. "Give it time, Cheeky. You're only 18. And have you seen our family? You'll be pretty big sooner or later."

"But I want them noooooow," Cheeky whined overdramatically and mostly jokingly, giggling afterwards. "Seriously though, I hope mine grow soon, I feel so small next to you two..."

Inky took another sip from his beer can and glanced over to Jim, whose ears were perked up to listen in too. They glanced at each other and Inky nodded to him, wiggling his eyebrows. Jim just stared at him blankly, though, so Inky sighed and leaned in, dropping his voice to a whisper. "What do you say we help my sister out with her problem?"

Jim gave him a wide grin. "Like we did with-?"

"Yep."

"I'm down," Jim said, nodding, and Inky grinned widely as he set down his beer can and stood up, heading over to the girls.

"Hey, ladies," he greeted them to get their attention, putting his hands on his hips. "Couldn't help but overhear that Cheeky's got a problem I think we could help with." He gestured with one hand towards Jim, who had gotten up and was standing behind him.

Bun and Jam both giggled a little, but Cheeky was quite taken in, staring up at her older brother. "Wow, really?"

"Uh-huh!"

Cheeky looked thoughtful and skeptical for a moment, but then shrugged. "Eh, even if this is just some ploy for you to get your rocks off, I'm sure it'll be fun," she said, getting up from her seat. "Okay, what've you got? Some kind of special injection?"

"You could call it that," Inky teased. "Come on inside with us and you'll find out."

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Cheeky stepped into Inky's bedroom as he had indicated, turning around and stretching her arms over her head. "Okay guys, so what's the plan?" she asked as Inky and Jim both came in after her.

"Wear this," Jim told her, holding up a dark red blindfold.

"And kneel on the floor, topless," Inky added, gesturing towards an open spot by his bed.

Cheeky snorted in amusement. "Look, if you wanted blowjobs that badly you could have just asked," she teased as she reached behind her to unfasten her bikini top, tossing it onto the bed as she was left in just the bottom half.

"You'll see," Jim promised, holding out the blindfold for her to take. "Well, you won't SEE, but... you get the idea."

"Uh-huh," Cheeky said, rolling her eyes with a smirk. She took the blindfold and started wrapping it around her head as she knelt down, giving Inky a smirk before pulling the fabric down over her eyes. "Look, I'm your sister, I know you two, and I know this is gonna involve your dicks in some way or another."

"You're not wrong there," Inky admitted, and she heard zippers being undone and fabric shuffling from her brother and cousin. "But we promise you're going to like the results."

Cheeky gave an exaggerated shrug, pushing her chest out a bit. But whatever comment she was going to make got cut off as she felt their hands on her tits – she was pretty sure it was Inky fondling her right tit while Jim played with her left. Giving a little groan, Cheeky leaned into the attention, especially as they paid special attention to her nipples, teasing over them with their fingers and giving them little squeezes.

"I hope this works, this'll feel so much better with big tits..." Cheeky mumbled. Inky took his hand away for a moment and then it felt slick when he brought it back, with Jim following suit right afterwards. As she pondered what that was about, she let out a gasp of surprise when she felt Inky's finger press right up against the middle of her areola, teasing the nipple directly, pushing it into the flesh of her breast. Jim did the same thing on the other side of her, and a shiver ran through her body as they kept playing with her nipples, teasing them and covering them with whatever slick fluid they had on their fingers.

"Whoa, what-!" Cheeky began, groaning softly. "That feels so weird! It's not bad though..."

"It's about to get better," Jim teased, taking his hand away. Unbeknownst to Cheeky, Inky and Jim were taking aim together as Inky brought his hand up to Cheeky's shoulder. Both of them held their cocks in one hand and moved them close to Cheeky's breasts, lining up with the nipples they had just been playing with. Inky kept his free hand on Cheeky's shoulder, while Jim held up his and silently counted down from three, lowering one finger at a time.

"You didn't have to stop," Cheeky murmured. "It was just new, that's all, I've-"

Both Inky and Jim pushed up against her tits again, this time with their cocks. Cheeky let out a gasp of surprise and reached up, tugging off the blindfold to see what the heck they were doing. Her brother and cousin both had their cocks shoved right up into her tits, indenting them as they pushed forward.

And then, to her surprise, they both sank into them and she felt her nipples stretching out around their dicks. "What the f-!" Cheeky began, tipping her head back in a moan at the strange new sensation. Both her brother and cousin were not small, stretching her out substantially, with Inky even bigger than Jim. They began to thrust, quickly drifting out of sync as Jim made quicker and shorter thrusts. "Uhnnh... how did you even fit in there...?" she groaned out.

"We've done this before," Jim told her, panting a little as he rocked his hips back and forth, his balls swinging between his legs. With Cheeky's breasts being so small he could only fit his cockhead and a couple inches of his cock into her, and Inky was barely able to get much more than his fat glans inside her.

Cheeky looked back and forth between the two of them, moaning from their short thrusts into her breasts. Was it really working? She reached down and cupped her tits, feeling over their curves, but it was so hard to tell. Inky and Jim's brief thrusts continued, both of them groaning, but then she was able to see it. As the two of them leaked pre into her tits, she could feel them getting a little heavier in her grasp, and she could see the other two rabbits were able to get more of their dicks into her before bottoming out against her ribs.

Her eyes widened, and eagerly, she reached out and took hold of their cocks, stroking them both as they thrusted. "It's working, keep going!" she said excitedly, grinning as Inky and Jim groaned from the extra attention. She jerked her hands over their cocks faster, paying attention to the slowly growing weight on her chest as her brother's and cousin's dicks throbbed within her breasts, all three of them moaning, the guys much louder as Cheeky's hands moved back and forth so fast they were almost a blur.

"Uhn, Cheeky, I'm gonna-" Inky groaned out, gripping her shoulder with one hand.

"Yeah, do it!" she called out to him, but it was actually Jim who shuddered hard first and pushed into her tit as far as he could go. His dick throbbed and the underside swelled out as his cum erupted into her breast, followed by Inky moaning a moment later as he shuddered and started to blow as well. Cheeky let out a shuddering moan as she felt the two of them filling her up, but even though she felt the hot, thick fluid gushing into her tits, none of it sprayed back out around their cocks. Instead the two mounds on her chest grew far more rapidly than before, swelling and plumping out, making Cheeky tremble and squeeze her eyes shut as she moaned out from the sensation.

The three of them were left panting, and Cheeky opened an eye and looked downwards. She was bigger, but... "Is that it?" she asked, reaching up and cupping her breasts. They were very good C-cups now, almost Ds, but after having Inky and Jim both blow a load into her she felt like they ought to have grown more than that. Plus, with Inky being more endowed, her right tit was bigger than the left...

...well, there was one easy way to solve all those problems. She leaned back, pulling off both of their dicks with a wet sound, her hands holding onto her tits to keep them held up. "Okay, you two swap places," she commanded, getting their attention. "Let's go again."

"Yeah, okay, just give me a minute," Inky gasped out between panting breaths.

"Come on, big bro, don't tell me you're one-and-done," Cheeky teased. "You're not gonna leave me with uneven tits, are you?"

"Of course not, just gotta catch my breath..."

"You're good for another too, right Jim?" Cheeky asked her cousin, who was stroking at his cock with one hand.

"Yeah, you know me, one's never enough-" he began, but Cheeky cut him off.

"Good! 'cause you guys promised me BIG tits, and these aren't even bigger than Bun's. So let's go again."

She cupped and bounced her tits insistently as the two guys swapped positions – bumping into each other at first, backing up, bumping into each other again, and then finally swapping as Inky grabbed Jim's shoulders and pushed him into the spot Inky had been standing in a minute ago. It didn't take long for them to get fully hard again – they were rabbits, after all – and Cheeky obligingly arched her back to push her breasts out towards them invitingly.

They slipped back into her with more ease than the first time, though Inky's bigger dick gave her a little extra stretch on her left nipple. But now that her breasts were bigger, there was more of them to thrust into, so as the two guys started to rock their hips back and forth, they were able to make longer strokes this time. "Ooh, that's so...!" Cheeky began, holding the undersides of her breasts to keep them steady for Inky and Jim to thrust into them, but she couldn't describe the feeling, and just moaned out instead.

She began moving her upper body forward and backwards as well to help meet their thrusts, but the two cousins couldn't keep in sync for the life of them; sometimes they'd slide in at the same time, making Cheeky groan out, sometimes one would pull out just as the other humped forwards, but most of the time they were slightly adrift.

Cheeky kept her hands under her tits the whole time, sometimes squeezing them when one of the other two was deep inside, making them moan out. Their pre had helped push her breasts over the edge into D-cup territory, but she wanted more. She looked back and forth between Inky and Jim as they thrusted into her nipples, both with looks of bliss on their faces, speeding up their thrusts as their dicks throbbed inside of her mammaries.

This time it was Inky who came first, but not by very much, the two of them moaning out together as Jim blew his load moments after Inky's first shot of cum erupted into Cheeky's left breast. She gasped and cried out as they both filled her up again, savoring every throb of their dicks she felt within her nipples, and the surge of heat from their cum that seemed to promptly get absorbed, bloating and swelling out her tits. She could feel her breasts swelling out in her hands, wobbling in her grasp, engulfing more of the two guys' shafts as her breastflesh expanded. Both Inky and Jim were struggling to stand as they trembled in orgasm, and were left panting when they finished.

Cheeky leaned back and pulled off from the two of them to inspect the results. She was well past a D, even DD, approaching E-cup territory now. Her breasts were big and soft and her fingers sank into them as she gave them a squeeze. Even her nipples had grown, though that wasn't surprising considering what they had been put through. After one load each from her cousin and brother, her tits were about even now.

But...

Cheeky looked up at Inky and Jim, smirking to herself as she cast her gaze back down to their cocks. They'd always been bragging about how many rounds they could last. "Tell me when you're ready to go again," she teased, giggling and bouncing her hefty tits in her hands.

--------------------

"They've been in there a while..." Bun remarked idly, looking towards the house. "Should we go check on them?"

"Nah, I'm sure they're fine, probably fucking or something," Jam said dismissively with a wave of her hand. "You know what Jam's like and I'm sure Inky's the same. Anyway, you wanna watch a movie later? I've been wanting to-"

The back door of the house opened up suddenly. "Heeey, check it out!" Cheeky called out cheerfully, running over towards the two older girls. She bounced and wobbled with every step: her tits were now absolutely massive G-cups big enough to reach past her sides and her arms, almost all the way down to her waist.

Bun and Jam both stared wide-eyed at Cheeky's immense cleavage, barely noticing an exhausted Inky and Jim slipping out with her to return to their seats. "What... how...?" Jam blurted out, staring in disbelief.

"Who cares how? I want that too!" Bun declared, getting up from her seat, uncaring as she knocked her glass over and marched over to Inky and Jim, who had only just sat down and recovered their drinks. "Come on, Inky, I'm your older sister, you've got to do the same for me too!"

"Yeah, Jim!" Jam shouted as she joined in. "She can't have bigger tits than us!"

Behind them, Cheeky merely grinned, rubbing her hands over her breasts. "Uh, sure," Jim replied, "How about tomorrow-"

"Nuh-uh, I'm not driving you home until I've got tits at least as big as Cheeky's!" Jam told Jim, pointing directly at him, fixing him with a firm look.

"And I want even bigger ones!" Bun demanded, cupping and bouncing her breasts, which now were modest compared to Cheeky's cleavage.

Inky and Jim shot concerned glances at each other. It was going to be a long evening...
