It always amuses me when I come across a fic where Erza dances like a normal human being, because Mashima gave us the comedy gold that it her canon dancing ability. This is way more fun, in my opinion.
Also, I will never let the Prince Frederick jokes die. Never.
Dread filled Lucy as as she gazed upon the still forms of her guild mates, lying prone upon the floor. The few with incredible constitution who had managed to remain standing did so while tottering unsteadily. Victims, all, of a cruel monster who knew not of mercy. The only survivor to escape relatively unscathed was Freed - and Lucy suspected the heavy and liberal use of enchantments on his part to achieve this great feat (for not even Vijeeter, master of all things dance, was unaffected).
Cold, heavy metal touched her shoulder, eliciting a half-muffled shriek from the blonde at the unexpected weight. Turning her head, Lucy peered into the eager, sparkling brown eyes that spelled out her demise.
"Lucy," her teammate began with a smile, "would you care to dance?"
To her horror, Lucy found herself unable to refuse the armored mage's earnest request. Erza's enthusiasm was an infectious thing, and that smile of hers was doing something heinous to Lucy's insides even before taking a turn on the dance floor. So what did it matter if she got nauseous due to Erza's... unique dance style?
With a nervous laugh, she nodded. "I feel a bit like a princess being asked by a knight!" she joked.
Erza's smile fell, and with it, Lucy's heart did as well. Oh no... had she offended her?
"Full armor would be hard to dance in," Erza suddenly stated, her expression intense. "But if you're a princess then..." Magic emanated from Erza's form, saturating the air with light. When the brightness faded, Erza stood before Lucy in...
"...Prince Frederick?!" Lucy squeaked. She was torn between amusement at the fact that Erza had kept the outfit, and mild horror at the fact that Erza had kept the outfit. Though it really shouldn't be surprising, Lucy realized, given the redheaded woman's hoarder tendencies. Although, she had honestly never expected to see that particular garment ever again, and would have been quite happy to relegate the memories associated with it to a distant, far-gone past.
Her teammate appeared to disagree with that sentiment. "Yes. I thought since I don't want to crush your feet while dancing in armor, a prince would be the next best thing to a knight."
Giggles bubbled up inside of Lucy at Erza's earnestness. "So a prince is lower than a knight, now?"
Erza nodded, an odd gleam in her eyes. "Knights get to protect their princesses."
Heat crept into Lucy's face at Erza's words. "Oh really? Guess I can't argue with that logic!"
This time, Erza bowed low, her crimson ponytail falling over one shoulder and her gloved hand outstretched to Lucy. "So... my princess. Might this knight in princely garb escort you onto the dance floor?"
Although she was no stranger to extravagant and lavish dance requests - having suffered through many a formal party growing up - Lucy couldn't help but be flustered Erza's invitation. Maybe because it was Erza, and what seemed cheesy for others came as natural as breathing to her, and she bore the usually trite customs and words with a sincerity that endeared rather than repulsed.
So Lucy placed her hand on Erza's. "I would be delighted to have this dance."
Erza's answering, soft smile took Lucy's breath away.
Sadly, none of this improved Erza's actual ability to dance.
Though Lucy could only call it half the source of her racing heartbeat.