Super Sub

Disclaimer: I do not own Supergirl or anything to do with DC. I do not make any money from the writing of this story.

*****

"Kiiiiirrrrrraaaaaaaa!" Cat Grant yelled loudly.

Kara Danvers sighed softly. She didn't mind that her boss continuously called her by the wrong name, because she knew it was a running joke or perhaps a way for Ms Grant to create some separation between them after one too many meaningful conversations.

She also didn't mind being yelled at by her boss, because it was all part of paying her dues like any normal human, and that was the point of this job, to feel connected to humanity. And she definitely didn't mind having a demanding boss, as Kara took pride in knowing that she could fulfil those needs with a smile on her face, and thus had become one of the very few of Ms Grant's assistants to keep her job for more than a week.

The problem was that it was now about 10 o'clock at night, meaning she'd worked for over 11 hours straight without a proper break, which she was pretty sure was against the law. She'd had to sneak a sandwich around lunchtime, but Ms Grant had confiscated her take-out delivery because she had too much work to do, meaning that Kara had skipped a meal, which was unprecedented. It was so unfair.

She was so hungry, and everyone else had gone home, where they could eat, and she was stuck here doing mostly things which weren't her responsibility, but Ms Grant insisted this was a test she needed to pass, and since there was no Supergirl emergency calling her away she stayed, even though she was hungry, tired and desperately in need of the stress relief she could only get from Alex.

Still, after a few long seconds Kara forced a smile to cross her face and called out, "Coming Ms Grant."

Reminding herself not to use her full speed Kara then stood up and walked into Ms Grant's office. Every other time today she had done this Ms Grant had been sitting at her desk and had barely looked up at her. A few times she had even been wearing her adorable glasses.

But not now. No, Ms Grant was standing in front of her desk, allowing Kara to admire the dress which no doubt cost more than what she made in a year which showed that for a woman in her 50s Cat Grant was still stunning, something which Kara couldn't help but focus on as she approached.

Then she realised Ms Grant was holding out a drink of Scotch for her, which made her smile, as while it wouldn't have any effect on her it was a sign that her workday was finally over and she was about to get some explanation of what all this was about, and hopefully a life lesson out of it that would make her long day worthwhile.

"I'm very proud of you Kira." Cat said softly, not missing the way that made Kara beamed happily, "You truly went above and beyond today, and I promise you, you will be rewarded for it."

"Thank you Ms Grant." Kara said brightly, taking the offered glass and casually taking a sip.

"I'm not talking about the drink Kira." Cat said flatly, "At least it doesn't have to be. It's really up to you."

Kara frowned, "What do you mean Ms Grant?"

There was a brief pause, and then Cat very deliberately looked her assistant up and down before admitting, "I had a very... informative conversation with your adopted sister today."

"Oh?" Kara blushed.

"Yes." Cat gently confirmed, taking a sip of her drink before continuing, "It confirmed a lot of suspicions I've had about you since the moment we met."

"Oh, oh really?" Kara stammered, trying to play it cool and failing so very hard, even nervously laughing as she added, "Like what?"

There was another brief pause and then Cat said, "Well for one thing... you're a sub."

"Oh?" Kara murmured, taking a deep breath before asking, "And?"

"Huh." Cat smiled, "I expected you to be more hesitant to admit that."

"Why?" Kara asked.

"Shame?" Cat offered with a raised eyebrow.

"But Subs are the ones with all the power." Kara pointed out in confusion, and then when Ms Grant continued staring at her added, "In a proper Dom/sub relationship there are safe words, which the sub can say at any time to make things stop. It's up to the Dom to stop that from happening, but if they make a mistake that's it."

"Well said Kira." Cat smiled, taking a sip of her drink before adding, "I must say it's refreshing to find someone your age who is so enlightened about sex. Especially someone who nearly never curses, and dresses like a school librarian. But then, that just made it more obvious what you really are. Which is cliché, but it's cliché for a reason."

"That's me, a big old cliché." Kara tried to smile innocently as Ms Grant took another sip of her drink, "Nothing abnormal about me."

"Very convincing." Cat said dryly, taking a few steps to her right to reveal what had been hiding behind her, "Kira, do me a favour and open that box."

Recognising the box in question Kara blushed a little bit and stupidly pointed and murmured, "That box?"

"Yes Kira, that box." Cat sighed.

"Yes Ms Grant." Kara said after a brief hesitation, taking a few steps forward and opening the lid to the led box, and then tried to hide her reaction to what was inside it.

"What's inside it?" Cat asked, as if she didn't know.

"A collar." Kara said softly, before admitting, "My collar."

"And what a beautiful one it is." Cat said, adding almost casually, "I spent far too much time debating on whether you had an owner or not. At first I assumed not, but the more I spent time with you the more I notice that you didn't show the usual signs of sexual frustration that comes from not regularly getting laid. You certainly don't reek of the desperation that particularly your handsome hobbit friend suffers from. But I was sure it was someone outside of work, because you showed little interest in anyone outside of James Olsen, and in time I realised that was merely a smokescreen to hide the fact that you're a raging homosexual. Which is understandable. It's hard enough being a working woman, let alone one who enjoys the company of other women. That's why I've been so particular about my own dalliances with my own sex."

"You're-" Kara began.

"Bisexual." Cat clarified, "And don't interrupt."

"Sorry Ms Grant." Kara quickly apologised.

"Now, where was I? Ah yes, your blatant homosexuality." Cat smiled, "Honestly I am ashamed I didn't realise it sooner, but in my defence I thought I was just flattering myself that such a young pretty thing like you, who doesn't seem like the goldigger type, really was interested in someone like me."

"How could you say that?" Kara asked.

"What did I say about not interrupting?" Cat scowled.

"Sorry Ms Grant." Kara apologised before quickly adding, "But I'm just so shocked you would think that. You're normally so confident. And you should be. You're amazing, and smart, and funny, and so, so beautiful. I, I feel honoured just to get to be around you."

Hiding a blush of her own for once Cat grumbled, "Such a charmer."

"It's the truth." Kara said firmly.

"Yes, well..." Cat murmured, briefly struggling to get them back on track, but eventually managing it, "My beauty aside I couldn't help notice how you looked at James's girlfriend Lucy Lane. The way you smiled at her. The way your body moved. The attraction was obvious to anyone with half a brain, which made me want to fire half the people in the room for not being smart or observant enough to notice. But I digress. The point is from that moment on I suspected that you were gay, and harbouring a crush on me. Both of which your sister was only too happy to confirm. But what I couldn't have imagine is that you were sleeping with your own sister."

"I'm adopted." Kara quickly reminded her boss.

"I know." Cat said, "Still it is very unusual. But then I suppose all of this is. And luckily for you I do like unusual... pick up your collar."

"What?" Kara asked, taken off-guard by the sudden command.

"Do not pretend you didn't hear. Or make me repeat myself." Cat said firmly.

There was another brief pause and then Kara did as she was told, again trying not to react as she picked up the little collar and smiled awkwardly at her boss. She also properly turned around for the first time since she came to stand in front of the box, mostly facing forwards as Ms Grant interrogated her, only turning around when it was appropriate, like to reassure her boss of her beauty.

Ms Grant stared at her for a long time, then at the collar, then back and forth as if she was expecting more of a reaction. Kara tried not to give her one, but it was difficult. Then Ms Grant slowly step forward, closing the distance between them, causing a little squeak to escape Kara's lips.

"It really is beautiful work." Cat said softly, adding almost casually, "I specially like the way these tiny little green stones are spread out in such a pretty pattern you could almost be forgiven for not realising it's Kryptonite."

"W, what?" Kara stammered.

"No need to play dumb Kara." Cat smiled softly, "Alex clearly realised she'd made a mistake when she handed this to me. It might have helped if she hadn't included the led box, but even then I'm familiar with Kryptonite enough to know it when I see it."

"Ms Grant, I-" Kara began.

"Kira, we both know you're not good at coming up with excuses on the spot, so how about we leave the excuses in till tomorrow?" Cat suggested, "I'm not looking for confirmation on that particular suspicion. I'm a lot more interested in confirming everything else, especially your interest in being my sub. So I'll make this simple. If that's something you want, you can put on your little collar and-"

As quick as she could without using her super speed Kara shoved the collar around her neck and firmly attached it. Then when her boss continued staring at her she timidly added, "Yes Ms Grant?"

"I wasn't finished." Cat scolded, "You and your sister have put us both in a very compromising position Ms Danvers. One I do not take lightly. If it ever got out that there was something... unprofessional about our relationship it would be beyond scandalous. It would not matter if I terminated your employment right now, or simply moved you to another department now or later. Actually, it might be worse. Bottom line is that I would be far better off sending you on your way now and then forgetting all about it, because really, sleeping with one's assistant? I'm not sure I could endure the embarrassment of being caught doing anything so clichéd. And yet... I think you would be worth the risk. Don't you?"

"Yes Ms Grant." Kara replied quickly, "I, I promise I would make it worth your while."

"If I doubted that, we wouldn't be having this conversation." Cat said dryly, finishing her drink, putting it down on her desk and then with a deep breath continuing, "And if we are going to do this, we're going to do it right. I know Kira, I want to get to the good stuff too, but first I need to make a few things clear. Firstly, and most importantly, you will tell no one about this. No one. I can't be clearer on that."

"What about Alex?" Kara asked, knowing it was a stupid question, but wanting to be clear.

"Well of course, if you must." Cat rolled her eyes, "But nowhere someone else can hear you. If you do, this ends. Understand?"

"Yes Ms Grant." Kara nodded.

"Good." Cat smiled, getting even closer to her pray, "It should go without saying that you need to do everything I say without question, regardless of what it is. Although I promise you, it will be nothing your sister hasn't signed off on. It should also go without saying that you can stop me at any time by uttering your safe word, which for us will be... Supergirl."

"Supergirl?" Kara blushed.

"Yes, Supergirl." Cat smiled again, although trying to make it not as wicked and gleeful as she felt inside, "After all, you were very outspoken about the name that I initially chose for our, mutual friend. And I can't imagine why we would discuss her, and to me the fact that we both know her makes this whole thing even more kinky. So I ask you, what could be more appropriate? Unless of course, it makes you uncomfortable for some reason..."

"No." Kara said weakly, "Supergirl is fine."

"Right then, let's move on to how you should address me." Cat said, "Like at work I expect you to call me Ms Grant. Not Cat, not Ms, and certainly not Ma'am. Especially never Ma'am. I have allowed you a little leeway when you have occasionally called me Cat at work simply because we have grown closer, you have proven yourself to be a good assistant, and more importantly a bright young woman capable of so much more. But as my sub I will not tolerate such familiarity. Do you understand?"

"Yes Ms Grant." Kara nodded.

"And of course I expect you to be professional around the office." Cat continued, "That means no looks, no smiles and certainly no touches or body language which could suggest there's anything unprofessional about us. And absolutely no propositioning me. I may do it from time to time, but I believe I'm a better judge of my surroundings than you are, and as the Dom I should have some privileges. But by all means, continue wearing those tight skirts and pants around the office. I do so enjoy those. And I definitely want you to keep bending over to grab something so everyone can stare at your ass, but only when I can get a good view of it. So essentially, just keep doing what you've been doing, you little slut."

Kara hadn't realised that anyone knew that was on purpose, and she certainly hoped no one else noticed, but she put that out of her mind for now and simply nodded, "Yes Ms Grant, I understand."

"Alright, let's get started, shall we?" Cat asked rhetorically, then just in case her assistant try to answer it she quickly added, "Bend over my desk and stick your cute little ass out!"

Just before that last order Cat had cruelly leaned in like she was going to kiss Kara only to pull back. It was a move that Kara was very used to receiving from her sister Alex, and made her wonder if Alex had recommended that particular move to Ms Grant. Then again, would Ms Grant take that level of sex tips from anyone? Surely she wouldn't need it? Would she?

Of course that little internal debate caused her to pause before doing what she was told, which made her flush with embarrassment. She was a super sub dammit, not some blushing virgin who didn't know what she wanted. She needed to get it together. She had a dominant older woman to impress.

Cat was already feeling impressed. That Kara hesitated was understandable, and she was happily able to forgive it, especially in this early stage of this new relationship. What was really impressive was that Kara hadn't even tried to deny the obscene things that her own sister, albeit adopted one, had said about her and had agreed to each one of her demands without any fuss.

And then there was that ass. Oh God, Cat was genuinely embarrassed that she would literally drool at the sight of Kara Danvers bending over her desk, placing both her hands upon it and pushing out her perfect little butt like the well-trained sub she was.

After maybe a full minute of just staring at that ass being framed beautifully by that skirt Cat was unable to stop herself from stumbling forward, reaching out and grabbing her assistant's inviting ass like the clichéd pervert she now was, shamelessly groping it as she growled softly, "Oh Kira, I'm so glad you like this kind of thing, because this beautiful butt was made to be spanked."

"Thank you Ms Grant." Kara replied cheekily.

It was extremely tempting to respond with a nice hard smack to Kara's ass, but because it couldn't be clearer that's what Kara wanted Cat simply glared briefly at the back of her assistant's head before going right back to groping her butt.

She mostly did this to tease her pray, but the truth was this was something Cat had been itching to do ever since Kara's first interview, and the longer she was her assistant the more Cat wanted to reach out and grab this ass.

Or maybe just give it a playful smack, like self entitled men did whenever they thought they could get away with it. Like some men had done to her when she was coming up in the business, and helpless to do anything about it.

So in a sense there was something almost poetic about this. Although there was nothing playful about the first time Cat finally smacked Kara's ass. It was hard and forceful, Cat suddenly taking both hands off Kara's cheeks to deliver the most brutal double smack she was capable of giving.

As a result Kara cried out in pain, although not nearly as much as she probably should have, considering the force behind that blow. which was perhaps another breadcrumb that this girl was exactly who she thought she was. Not that Cat concentrated on that right now. No, she was far too busy dishing out half a dozen slaps to her assistant's perfect behind, officially beginning the spanking. Sort of.

In Cat's mind it wasn't quite official until she did one thing first, so grabbing the bottom of Kara's skirt she announced, "I'm sorry Kira, but I think a proper spanking should always be bare bottom."

"Me too Ms Grant." Kara grinned, "Please, expose my bare butt so you can spank it good and hard."

"Wow, you really are a little pain slut, huh?" Cat grinned.

"Uh-huh." Kara moaned, before a wicked smile crossed her face, "And not just a slut for pain."

Honestly that last part didn't even really register as Cat was slowly pushing her assistant's skirt up, bit by bit revealing the ass she so adored. As if that wasn't amazing enough one thing quickly became apparent, Kara was wearing a thong which somehow made her ass even more inviting, and that she was wearing something else which made Cat think she was going to cum on the spot.

Once the skirt was firmly secured around Kara's waist Cat slowly pulled down the young girl's thong and spread her cheeks so she could get a good look at what was in between them. Which wasn't exactly a surprise, but to actually see her innocent assistant's ass hole being stretched open by a butt-plug was overwhelmingly erotic. So much so that Cat lost her voice for a few long seconds.

When she found it again Cat playfully scolded her assistant, "A butt-plug, really Kira?"

"I told you Ms Grant, I'm a slut." Kara replied shamelessly.

"Well..." Cat grinned as she continued staring at the plugged butt in front of her, "You know what happens to sluts, don't you?"

"Oh yes Ms Grant." Kara nodded eagerly, "They get spanked."

"And you want that?" Cat growled.

"Yes Ms Grant." Kara quickly confirmed.

"Then beg for it." Cat pushed, "Begged to be spanked in your boss's office like the clichéd slutty secretary you are!"

"Please Ms Grant, spank me! Spank me hard!" Kara started begging immediately, "Spank my slutty little ass! Please? I want it so bad. Please give it to me Ms Grant. Spank your assistant while she's bent over your desk and offering you her ass. Spank me hard! I want my boss to spank me in her office like the clichéd slutty secretary I am. Please Ms Grant, spank me hard! Oh God yes!"

Kara let out a cry of joy from the first strike to her ass. She then bit her lip and tried, mostly unsuccessfully, not to let out any more sounds of enjoyment as the spanking officially got underway. To be fair Ms Grant was clearly going easy on her in the beginning, not only using a fraction of her strength but giving her plenty of time in between each blow to recover, so Kara didn't think her reactions were that suspicious.

It also helped that she was very used to this kind of teasing spanking from Alex, so Kara was able to keep herself from letting out sounds of frustration. She even enjoyed it to some degree, especially the way that Ms Grant would try and caress the pain away in between blows, which was unnecessary but she liked being felt up as it was assigned just how much Alex, and now Ms Grant, loved her butt.