Double or nothing grab-battle!

Ruby tied Yang's voluminous bikini top as best she could under the circumstances. Looking down at her front, she frowned. The roomy yellow garment was quite loose around her modest bosom, despite how much string she had pulled back while putting it on. The inside edges of the cups drooped a lot, splaying out far to expose her breasts to the crisp sea breezes and sharp leering eyes alike.

Yang was snickering, and Ruby lifted her head to shoot a glare at her unbearable big sister, only to stare with blushing captivity at how her own bikini top sat on Yang's figure.

The little black and red number, plenty sufficient to cradle Ruby's perky buds semi-conservatively, was stretched flat in the effort to contain the voluptuous blonde's ripe melons. The two taut triangles of fabric pressed in the bountiful mounds, a salacious expanse of underboob poking out beneath the poor overtaxed material. Yang's nipples were also in stark relief, even through the dark fabric, the peaks of her breasts standing scandalously stiff and plainly poking through her coverings. Yang's smirk only widen as she took in her baby sister's gape-mouthed trance.

"What's the matter Rubes? Jealous your colors go with me better than mine go with you?"

That brought Ruby out of her spell, and her face snapped into a simply adorable scowl as she attempted to throw daggers through her eye contact with Yang.

"You're stretching out my new swimsuit."

"Consider it a benchmark of what to grow into when you get it back," Yang threw back indolently, "If you get it back."

Ruby intensified her glare at Yang's blithe perverseness, "I'm taking my bikini back Yang, and I'll just keep holding onto yours in the meantime if you're so proud of that chest."

"Oh yeah Lil' Red?" Yang heckled, eye racking Ruby's figure, "Come try it, see how much clothing I let you hold onto."

The two half-sisters stood at a stand-off for some moments, sizing each other up. A droplet of water dripped from Ruby's hair, landing on her collarbone and slipping down her chest, tracing over the curve of on breast and subsequently drawing Yang's eye to the edge of Ruby's candy-pink nipple. Yang licked her lips as her eyes took in the expanse of flesh Ruby left bare and open.

Ruby found herself momentarily distracted again, as Yang's incestuous cravings caused her skin to flush and her chest to heave. The rhythmic swell and dip of those massive tits under that tiny top was hypnotic, those mountains of female flesh straining against their confines, threatening to burst the article of clothing to be free and in Ruby's hands. She gulped audibly at the thought.

The seconds ticked by as the two girls let the tension climb. Just before the thread broke and the two young women fell into each other in mutually-depraved sororal passion, Ruby sprang with a war cry, determined to seize Justice first and foremost!

Blake pulled a bookmark out of her bag and marked her page to pick up from later. It was too bright out to read comfortably. A high-pitched, comical yell brought her attention to the water. Ruby had just jumped at Yang and pulled them both down to their necks in the water, and the two sisters were now in the middle of an oddly heated-looking tussle.

"Should they be rough-housing like that in the water without supervision?" She mused aloud, only half-addressing Weiss. The petite, grumpy heiress gave a haughty 'hmph' of answer anyway.

"They're big girls, the water's shallow, you're watching, they'll be fine..." She ascerted, each sentence fragment delivered in a sleepier and sleepier voice, "*Yawn* Let them tire each other out." And so declaring, the little princess rolled over and drifted off.

Blake snorted in kind, gazing over at Weiss with wry amusement before a wave of tiredness washed over her too, the heat draining the cat Faunus of energy just as much as the pale rich girl.

"You're right I guess... except for me watching..." If Blake was gonna say anything more, it got lost in her rapid check out of consciousness, the non-human girl only able to tug Weiss' wide umbrella over towards her to more evenly split the shade between them before joining the heiress in slumber.

Ruby and Yang grappled and yanked at each other fiercely. A contest of wills and techniques as intense as any sparring match played out in those shallows; Ruby jabbing a grasping hand at Yang's chest, Yang swatting the limb away and trying to hook her fingers around Ruby's (hers) top, Ruby darting back out of her older sister's reach before engaging the fray all over again.

The water got rougher all of a sudden, and the two girls found themselves being pushed against each other. Hands accidentally-on-purpose roamed up and down each other's curves. Ruby tugged Yang's bottoms down her thighs while motorboating her at one point, Yang retaliated by giving Ruby a frontal wedgie, fingertips tracing Ruby's snatch as she scrambled for purchase.

By chance the two off them fell off-balance and simultaneously reached for the others' shoulder to steady themselves. As both girls grabbed the strap of her sister's stolen bikini, another large wave came and swept them back. As one they rolled away from each other, their bikini tops ripping off in the other's grip. As they helplessly spun around, the bikinis became wadded up in their grips, and when crashed on the sand bank Yang and Ruby reflexively threw their hands back and unthinkingly launched their tops away to be rolled by the water out of their reach.

Ruby spluttered as she pulled herself up from the shore. She blinked blearily in the direction where Weiss and Blake lay sprawled in their chairs snoozing, before glancing at Yang over in the side and realizing something dreadful.

"Yang, my top!"

"Ruby, our tops!" Yang rebutted, but with considerably less humor than earlier as she scraped sand off her boobs.

"Where are they, where are they?!" Ruby practically squawked, twisting to and fro to try to spy the discarded articles on the nearby water, to no avail.

"Uhh..." Yang started, "I think they're over-" before she could finish a seagull flew to the patch off water she was pointing at, skimmed the surface, and lifted up again with a yellow and dark red bundle in it's beak.

"Oops."