Strip and have her start dancing.

Ruby considered what to do with Yang first, having made up her mind to let her sister be her sex ****. She thought about taking things slow, but discarded the idea. She was always the type to go all in on things once she decided to do them, and this would be no different. "...alright Yang," she said, taking a deep breath as she steeled herself. "Can you reform your legs?"

"I can, Mistress, with your permission," Yang nodded eagerly.

"Then do so, and get that sexy body of yours dancing while I get naked." As she spoke, she stooped down to start unlacing her boots, but kept her eyes on Yang.

"Oh, yes, Mistress!" Yang grinned, raising her arms above her head as she began to slowly rotate her hips, and simultaneously twist her torso back and forth subtly, giving her large boobs a nice bit of bounce. As she did, her tail detached from the spout of the lamp, and split, coalescing back into her legs, which were immediately in motion to maintain her dance.

Ruby was smiling softly, still barely able to believe the situation, but at the point where she was prepared to enjoy it. Yang's own enjoyment was also evident, her exuberant smile visible behind her veil as her body continued to move. Ruby slipped off her boots, one after the other, wiggling her tights clad toes as they were freed.

Yang twirled around a full 180 degrees, maintaining the gyrations of her hips to show Ruby her ass. The simple act of obeying Ruby and using her body felt so good and fulfilling that she was honestly having the time of her life, and it showed. Ruby straightened up, unclipping her hooded cloak and letting it flutter to the floor. Her nimble fingers then immediately worked on the corset part of her blouse, loosening it.

Yang proceeded to lean forward, placing her hands on her knees, and twerking her derriere for Ruby's viewing pleasure, jerking her hips and bouncing her ass cheeks. She gave a sultry look back towards her sister and Mistress, working her backside for all it was worth. Once Ruby had gotten her blouse loose enough, she reached down for the hem of it, pulling it up, and off over her head. Beneath, her chest was clad in a lacy black bra. She then reached for her skirt, undoing the fastening at her hip, loosening the waistband enough that the garment simply dropped down her legs.

Yang twirled back around as she tilted her shoulders back, emphasizing her breasts, and continuing to gyrate her hips. She consistently altered the tempo of her movements, sometimes moving slow, then speeding up. Her hands then began to run over her own body, both on the sheer silk covering, but failing to conceal, her most intimate spots, and over the completely exposed skin. Her belly undulated, further drawing Ruby's gaze.

"Mmm," Ruby bit her lip in arousal as she continued to watch her sister, now her all too willing ****, move her absolutely divine form in absolutely lurid ways meant to draw her gaze. It was most certainly working as she reached behind her back, quickly unclipping her bra, and sliding it down her arms. Her small but perky breasts drew a longing glace from the new genie, their size contrasting her own, but they were definitely appealing in their own right.

Yang proceeded to extend her arms out and twirl a few times, bouncing on the balls of her feet to make her body continue to move, tantalizing her Mistress with every motion, completely eager to please. Ruby wasted no time, hooking her thumbs into the waistband of her tights, and her panties underneath. She slid them down her hips, before sitting down and continuing to move them down her legs, lifting them as if moving into a fetal position before pulling both garments clear of her feet. Now naked, she dropped them both, her gaze steadily growing more and more lustful as she watched Yang now move her hips in even more complex motions, like a figure eight.