It's really, really hard to get Arisawa Tatsuki to dance. It isn't that she doesn't like it, but when you've vowed to protect Inoue Orihime, most of your time is spent beating off the perverts whose hands slip just a bit lower than the busty girl's waist. And most guys either consider her 'one of the guys' or are petrified of the bully hunter, so they don't ask her to dance.
But when Tatsuki does dance...
She isn't magically more graceful or beautiful when she dances. Anyone who knows Tatsuki would agree that the spiky-haired girl is neither graceful nor beautiful in the traditional sense. Striking is perhaps the best word to describe her. She's certainly not clumsy, as her victims can attest, but her movements are precise and forceful like the karate she's trained in. Her looks are memorable and aesthetically appealing, particularly if you go for the punk look, but Tatsuki utterly lacks the attractiveness, sex appeal, gentleness, and most other concepts that one associates with beauty.
When the second-level black belt finds it in herself to dance, she dances the same way she fights. Fists clenched, feet stomping, sharp elbows lashing out at whoever's too close. Her dark hair is made darker by the sweat plastering part of it to her scalp, the rest flying around her face as her head dips and bobs with the music. Tatsuki always comes off the dance floor grinning broadly and laughing.
Her dancing is as passionate as she is, moved by whatever music happens to be playing at the time. Even if the so-called 'Dragon of Karakura' doesn't like the song, she dances for the beat, dances because she can, because she's gloriously alive. To her it's as much of a battle as trading punches with some poor idiots who decided to pick on a younger kid, fighting to prove that she won't lose to exhaustion.
Tatsuki was made for combat. She was made to roar as loud as her namesake and charge into battle, sword swinging and blood dripping from a thousand wounds. She wasn't made for war, never meant to wear a samurai's armor. Tatsuki is a fighter only, not a warrior, lacking elegant finesse and the arts of peace and making up for it with raw willpower and bull-headed hard work.
As tired of Chizuru's attempts to molest Orihime as the second-strongest girl in Japan is, she lives for those moments when she can fight and protect. Maybe that's why Tatsuki put Ichigo's head through a window and screamed at him when Orihime disappeared. She couldn't fight the forces that had taken her best friend because she didn't know who had done it, couldn't protect Orihime from Aizen's machinations because she was only human and he was a Shinigami who aspired to be God.
So for now, the dragon girl dances and forgets all about that as she fights her own battles in the world of the living. She fights delinquents and bullies as she always has, but she fights herself too. Fights the inadequacy that makes her powerless to fight the soul-eating monsters that ravage Karakura daily, fights the 'What if I'd done this?' sensation that lingers constantly, fights to not be left behind again.
Because if there's one thing that a soldier fears, it's losing everyone who's ever fought beside her.