Here is my first femslash ever... I'm still missing the ambiguous Corah relationship... I hope you'll like this prompt :)
(Pre-canon, rated K+)

1892

"How would you like to go to a ball O'Brien?"
Sarah's hands froze on Cora's shoulders. She had been working for the young lady for two years, and she felt the woman was quickly gaining confidence now. She still behaved like the American lady she was and would always be, but she seemed to fit in her new life. Still, she kept on relying on her lady's maid each time she felt homesick, knowing well that her dear O'Brien missed her home and family.
Cora's gaze searched Sarah's in the mirror, and once again, Sarah felt her blue eyes melt her heart. She had taken a liking on her mistress. Cora respected her like no one had before, and was always kind and thoughtful. She was the lady Downton needed.
"A ball m'lady?"

Sarah proceeded to untie Cora's long hair to comb them delicately. She would always admire those shinning mahogany curls running through her fingers, reflecting the light of the candles.

"Yes, a ball. Robert wants to organize a reception to celebrate lady Edith's birth. I'd like everyone to dance."

Sarah began to tie Cora's hair in a neat braid with a wry smile.
"If you don't mind me saying, it sounds like an American thing to do."
The maid saw the young woman's face lighten, and a smile play on her thin lips.

"This place is too dull. I feel invested with the mission of shaking up things a bit. And I would enjoy seeing you dance very much." Cora said, playing with the silver comb.
"Me m'lady?"
Sarah didn't need to look into the mirror to know she was blushing deeply at the mention of her dancing in a ball.
"Yes, O'Brien, you. Of course Lord Grantham and I would open the ball, but for the second dance, you should be the one dancing with him, and I with Carson."
Sarah went still. She certainly didn't mean to make her employees dance, did she? Cora sensed her disbelief, and tilted her head, still looking at her through the looking glass, careful not to move too much to let O'Brien do her work.
"What is it dear O'Brien?"
Sarah opened her mouth, then closed it, unable to turn her thoughts into words. Finally,she sighed.
"Forgive me m'lady, I would feel bad taking his lordship away from you for a dance."
Cora tried to suppress a laugh, but her shoulders jumped, and eventually, she giggled. In other circumstances, the young maid would have been delighted to see Lady Grantham laugh, her eyes twinkling, but she felt the whole situation was awkward. She didn't dare tell she couldn't dance at all, she had never learnt how to.
When the countess saw how bad Sarah felt, she stopped laughing and shook her head slightly.
"Are you afraid I would get jealous? Dearest, you dress me and undress me every single day, and his lordship doesn't have anything to say against that. Why would I be jealous of you dancing with him?" She asked with a gentle smile.
Sarah focused on her breathing. She was feeling played with. Caught up against a wall. She was the mouse and Cora was the cat, the grinning cat, happy to have a thing to play with.
"It's completely different." She stated, as normally as possible.

"Of course it must be." Cora agreed, with a mysterious, playful smile that made Sarah wondered if, maybe, she knew, deep inside that her maid was not completely indifferent to her.
She felt a strange kind of admiration for her that grew deeper and deeper everyday, and she feared she knew what it really was... She had felt the same once, and had ended up heartbroken.

She tried to focus on the task at hand. She tied Cora's hair expertly with a nice blue ribbon matching the color of her eyes.
"So, will you dance, Sarah?"

Her stomach clenched when she heard her name come out in a pleading tone from Cora's lips. And oh, those icy blue eyes, hoping for some kind of approval from her... That was too much for O'Brien. She needed to go away before she could do anything she would bitterly regret.
"I must say I find that rather intimate m'lady." She said, blushing.

A smile crept on Cora's lips, and Sarah wondered what was coming next. Cora could make her do whatever she wanted her to do, provided she added one of her cute smiles to her request. But dancing with Lord Grantham? She knew he didn't approve of her, right?

Cora did the one thing Sarah expected the least. She rose from her chair, still wearing her party dress, her long braid falling on her breast. She looked dignified, young and pure, womanly despite her young age. Sarah couldn't move, her mistress was too close to her, and she could feel her heat radiating from her body, and a faint smell of wine on her breath. The most striking and unsettling thing about Cora was that one couldn't read any emotion on her face. Her face was the finest piece of china, pale and flawless. And like a doll, her lips were pinkish and her eyes were a light shade of blue that Sarah had only seen once before- The same colour as a blossoming flax flower. Her smell was heady, the maid knew the fragrance well, it was one of the most expensive and 'à la mode' French perfumes, made out of roses. Her mouth went dry when Cora looked at her expectantly. What was she supposed to do? Normally, she would have undressed her to help her into her nightgown, but she could see it was not what the lady wanted. She froze on the spot, unable to do anything else than staring at the crook of her mistress' neck.

"You have never danced, have you Sarah?" Cora asked, scrutinizing her maid, her eyes only slits now, as if she was trying to read through O'Brien's curious expression.
Could Sarah lie to her? Was she entitled to? It seemed like a bad thing to do... Actually, she couldn't remember dancing was part of her requirements to be a lady's maid. And it was too late to lie, as she had already waited far too long for a lie not to sound suspicious coming out of her mouth... So she detached her gaze from Cora's body and looked at her feet, shaking her head.

She felt ashamed now, and she wanted to run off to her room, lock herself in and cry out of frustration. She had been reared in a farm, her parents had survived the famine and left Ireland shortly after, learning her how to dance properly in a ball wasn't part of their priorities. Feeding her, on the other hand, was. Thus, she could milk a cow and kill a chicken with her bare hands and cold heart, but dancing? Impossible.

Suddenly Cora's thin arm was around her waist, and she felt she was going to faint. She tried to focus on her breathing, as she realised she had not released a gulp of air since Cora had risen from her seat.

"Let me guide you."
Instinctively, as if she had done that every day of her life, Sarah put one of her hands on her mistress' shoulder, smooth skin touching the silk of her salmon dress, while she felt Cora's long fingers wrap like delightful snakes around her right hand. The young maid was very much aware of her mistress' knuckles resting in the palm of her hand, of her thumb gently caressing her own knuckles. From the corner of her eyes, she noticed Lady's Grantham's gloves carelessly abandoned on the bed.

Her heart was beating faster every second now, and when Cora began to sway, first slowly to let her get used to the new steps, she realised her legs were hard as rock, and her knees were weak. Without even being aware of it, she was resisting her lady with all she had. The truth was that her body was enjoying the contact too much to her liking. Cora must have felt it, as the grip on the crook of her back lightened and she gazed at her maid with a half-smile. There was no word needed. Sarah understood that the slightly older woman wanted her to trust her. Gradually, Sarah's defense went down. Every layer of protection she had woven over the past years fell one by one, and soon enough, she was flying, she had no understanding of what was happening. Her feet were following Cora's confident steps on their own independent will, and she had the strangest impression that the only thing keeping her in a standing postition was Cora's arm around her.
Their bodies were not touching, except for those few times when Sarah was lost in contemplation and accidentally missed a step, ending up brushing against Cora's frail body, causing her to giggle softly and to strengthen her grip on the maid to keep her from falling.
There was no sound around them, no music to guide them, apart from the usual mouse steps in the hallway, proving they were not alone in the house. And for all she cared, Sarah was alone. She felt lonelier than ever, so close to the damn woman who made her feel giddy, and at the same time, aware she could never be as close to her as she would want to.
By the time Sarah surrendered completely to the silent communion, the moment was over. Sarah did not realise they had stopped dancing before Cora talked, one of her hand still holding Sarah's.
"Do you still think it to be intimate, Sarah?" She asked, dead serious.
O'Brien shrank from her mistress' touch. She was quickly regaining her senses, and she felt awfully wrong to be that close to Cora. She cleared her throat and turned away from the lady, looking for her nightdress.

She didn't see Cora try to suppress a grin threatening to creep on her face, by bitting her lower lip, as satisfied and victorious as a cat after a sucessful hunt.

Sarah felt anger burn in her chest. She was angry with Cora as she wasn't paid to bend to her every silly, girlish demands. And she was angry with herself as well, for not being cold enough toward the damn woman. She would have to work on her ability to stay perfectly distant and professional. Cora was not to become a friend, she was her employer.

What about the ball? Well, Sarah thought dancing was definitely intimate, and the worst thing about all that was that she still had to undress the lady to put her to bed...