Disclaimer: I do not own Supergirl or anything to do with DC. I do not make any money from the writing of this story.
*****
Kara Danvers, a.k.a. Supergirl, was bored. She'd had quiet nights before, but this had to be an all-time record low criminal activity. Which on the one hand was good because it proved that people were thinking twice about committing crimes in her city, but on the other hand it led to incredible boredom. Normally there was some petty criminals stupid enough to try something, or something that resembled a threat stepping up to her, but this time there was nothing.
Not even an accidental fire for her to save a few people from. And the second she heard about something in a different city in other superhero dealt with it, which got irritating after a while.
At least she comforted herself with the knowledge that once she returned home to be greeted by her loving big sister, and that definitely wouldn't be boring Kara thought with a smile. Thoughts of what exactly they would do had been playing throughout her mind throughout the day, as they always did, but it had been particularly useful as her working day had turned out to be just as dull as her time as Supergirl.
Ms Grant hadn't given her much to do, which was a startling contrast to last week, just before they had sex for the first time. Kara smiled again as she thought how that first time had basically been repeated almost every night this past week, except for the weekend which was sister-sister time, but tonight it was Ms Grant who was busy and Alex who was available. Almost like they had a schedule or something.
Whatever the case it was tough for Kara not to change her schedule and fly straight for her sister Mistress, but somehow she was able to hold back and spend at least a few hours patrolling the skies before returning home for the treatment she so desperately needed. Although when she finally did she got like the best surprise ever, as not only was Alex waiting for her, but so was Ms Grant.
Having a really good feeling about this it was tough for Kara to contain her smile, but while this might mean she would have a really good time later she had to remember that Ms Grant didn't know the truth, and therefore she quickly needed to come up with an excuse of why she was here.
"Alex Danvers, Ms Grant, what a wonderful surprise." Kara beamed, "I was just looking for Kara Danvers. Have either of you seen her?"
Cat smiled, "Hello Kara."
As her sister looked surprised, then gave her a look, Alex sighed, "Don't look at me like that. She already knew."
"And I just spent like an hour signing a ridiculous amount of disclaimers for the DEO, promising not to out you or them, or the kinds of things your sister and I do to you." Cat said dryly, taking a long sip of the expensive drink that was in her hand before adding, "Alex insisted on that last one."
"The point is, you were sloppy Kara." Alex glared angrily.
"Please, it's just glasses in a ponytail. I don't see why you people think that would work." Cat pointed out, "I mean sure, perhaps the people passing on the street wouldn't notice, but anyone who spends more than a few seconds with you has no excuse."
"It's more effective than you might think." Alex said dryly, "Besides, do you want an excuse to punish her or not?"
"We don't need an excuse to punish her darling, where her owners." Cat chided her new friend and Co-Mistress, before turning her attention back to her assistant, "Isn't that right, Supergirl?"
Smiling nervously Kara replied, "Yes Ms Grant."
"Good. Now we're all on the same page..." Cat said, briefly downing her drink and putting the last down on the table beside her walked forward slightly and ordered, "Get on your knees."
"Yes Ms Grant." Kara gave another nervous smile before falling to her knees in front of her boss.
The sight made Cat's breath hitch, then she took another step forward so she was directly in front of Kara and then started sliding her hand through her hair, "I've waited a long time to see you like this, in your pretty little costume. So don't even think about removing it! We'll move it aside as needs be, but tonight I'm fucking Supergirl. Understand me, Kara?"
"Yes Ms Grant." Kara said softly.
"Stay where you are Kara." Alex ordered softly.
"Yes Mistress." Kara quickly replied.
"It's Mistress Alex, tonight." Alex corrected.
"Then yes Mistress Alex." Kara smiled happily.
As she spoke Alex stepped forward to reveal Kara's kryptonite collar, Kara happily moving her head to the side to make it easier for Alex to strap it around her neck. The second it was near enough to her she felt weaker, and the second it was strapped around her neck she had to grit her teeth to stop herself from whimpering.
Since introducing it into their fun time Alex had been experimenting with the collar, constantly adding and subtracting tiny kryptonite stones to try and find the right balance which would finally allow Kara to feel pain like humans did, while not actually doing damage themselves. They still hadn't found the right balance, but this was pretty close, and even though it hurt Kara liked it, because she was a total pain slut. Or, as she preferred, a Super Sub.
"Good, now crawl around like the little dog you are." Cat ordered with a wicked grin, eventually adding, "And bark for us."
Alex wasn't sure how she felt about this part. She got that it was supposed to be humiliating for Kara, and from the blush colouring Kara's cheeks after each of those commands it clearly worked, but to her it was just a little silly. It was near enough the only part of Cat's plan she disapproved of though, and not by much.
After all, considering what else Kara enjoyed, and what that super durable body of hers went through on a regular basis, this was nothing. And Cat seem to get a real kick out of it, and it was now within Alex's best interests to keep her new friend happy. So she kept her mouth shut for a few long minutes while the mighty Supergirl crawled around her own apartment.
"I suppose that will do. Supergirl, lay your upper half on your coffee table and stick your ass out. It's time for our Super Sub to get a super spanking." Cat commanded.
Unsurprisingly Kara swiftly obeyed this command, but slowly enough that her Mistresses could enjoy the sight of her crawling over to the coffee table and then bend over it to present her ass for a spanking. After all, Alex was the one who trained her. What was surprising was that Cat didn't order Kara to expose her ass. Alex even opened her mouth to give that order, but quickly closed it again when it became clear what Cat wanted.
As it should have been in the beginning. After all, the first time Alex saw Kara in her cute little Supergirl outfit the first thing she wanted to do was slowly peel it off of her. Or more accurately move part of it out of the way so she get to what she wanted, which was exactly what Cat did after a few long seconds of just staring at that ass.
Then up went Kara's skirt and down went her panties, exposing that beautiful little butt which was enough to make Alex's mouth, and another part of her, water with anticipation. Of course it had the same effect on Cat, who moved back so she could stare at that ass again, before flashing Alex an expectant look. She had to do it a few times for Alex to realise that Cat was expecting her to get her paddle, causing Alex to roll her eyes and huff.
She wasn't one of these woman's employees, or slaves. If Cat even knew the difference, Alex thought with a grumble. She should let the rich woman get her own damn paddle. But such arguments could wait until later. For now Alex was eager to get to the spanking, so just this once she grabbed the paddles and returned to her position behind her sister.
As soon as she handed Cat hers the rich woman gave Kara's ass a hard smack with the paddle, from the looks of it using every ounce of her strength on that blow. It even had the mighty Supergirl crying out loudly, although it was mostly a cry of joy. Cat then gave a smug smirk at Alex, who returned it with a glare.
Then a smile as she raised her hand and easily out did Cat's strike. Alex gave Cat a smirk of her own, the two Doms then staring at each other for a few long seconds before turning their full attention to their beloved Kara, partly to give the woman that they both adored what she so desperately wanted, and admittedly partly to outdo each other.
Kara had enjoyed the humiliation of acting like a little doggy, the collar around her neck enhancing the experience and helping her get into character. Of course she was also anticipating all the fun they were about to have, most likely including a nice hard spanking. Although she hadn't quite anticipated just how hard that spanking would be, or just how much she would receive.
Maybe it was because despite Mistress Alex's protests they were using a large amount of kryptonite, or maybe Mistress Alex had a problem converting weapons into BDSM equipment, again, or maybe it was the fact that it was two women spanking her at the same time, or more likely a combination of all three of those things.
