Rainbow awoke feeling like she had just ran one-hundred Running of the Leaves races. Her legs were sore, her mouth was dry, her joints were stiff, and her pussy felt… satisfied. More so than a good night of clopping or even the last time she’d had sex.

As the pegasus stirred on the sheets, she had no idea what time it was, or even what day it was. Last night had left them both worn out and exhausted, more so than she’d ever felt in her entire life.

A pleasant smile appeared on her face as she recalled what they had done, or for that matter, even how long it had taken them before they made it up the stairs. Expermination, yeah right right, Twi. She’s definitely got a little freak in her.

Her thoughts made Rainbow realize a fundamental truth: The princess was not in bed with her. The cyan mare shot up, far too quickly for her body’s liking. “Oh, dumb idea, Rainbow,” she said, raising her forehooves to rub away the rush of dizziness. A familiar soft voice nearby startled her, causing her to look up and see the missing princess.

“I don’t know about that, I’d say what we did last night was an awesome idea,” Twilight said, smiling softly as she stood at the edge of the bed.

Rainbow looked at her, taking in the mare like she had just teleported in out of nowhere. This was still the lovable egghead she had come to know as one of her closest friends, but something was different now. Twilight’s smile, alight as it was, held something Rainbow couldn’t quite pin down, at least not at the moment. Yes, this was still Twilight Sparkle, but just a “rule-free” Twilight. The six ear piercings were still split between her two ears, the spiked collar was still around her neck, and the most telling of her new features, the rainbow lightning bolt tattoo still upon her chest.

Rainbow felt the conflicting emotions of happiness to see her and regret over what she had done. Well, some of what she had done. The pegasus’s head dropped to the soiled sheets and mattress cover. “Sorry, Twi.”

“What for?” Twilight tilted her head to the side questioningly, taking a step closer to see into Rainbow’s eyes.

“The, you know...”

“Oh, still worried about that?” Twilight asked. A soft chuckle left her lips as she shook her head at the thought of ‘The Rainbow Dash’ being sorry for being a bad influence on somepony.

Rainbow raised an eyebrow, but before she could comment another thought crossed her head. Oh, yeah, I guess that means I lost in the end, doesn’t it? “So I guess this means I’ll start being a bookworm like you?”

Twilight cocked her head. “What do you mean?”

Rainbow Dash, a bookworm? As much as the old me would've liked that idea… I’ve got something else in mind. I wonder if Cadance’s offer still stands? Twilight thought as she watched the pegasus roll her eyes.

“Twi, don’t play coy, you won the bet, that means I gotta shape up and fly right. I gotta start reading books at the library each day and all that junk, right? Be a goody four-hooves. Right?”

Twilight chuckled as she jumped up on the bed, moving close to the pegasus so their muzzles were only a few inches apart. “Those weren’t the terms of the bet, Rainbow.” In truth, even if she didn’t have other plans, that wasn’t what Twilight wanted in the first place; she’d just wanted Rainbow to take her responsibilities seriously.

“Yeah they were. If you could buck the rules for a day that means I gotta shape up and fly right.” Rainbow was too focused on their conversation to notice the alicorn invading her personal space, not that it mattered much after last night.

Twilight grinned as she concentrated on a spell, she replayed the exact teams of the bet.

“You’ll do whatever I say? No fighting, no nothing? You’ll just do it, and you will not go back on it?”

“I-I… I don’t understand,” Rainbow muttered, her eyes staring off into the space above Twilight’s head.

“You said you’d do whatever I asked of you,” Twilight said, her hoof slowly sliding up Rainbow’s chest.

“Yeah, you know, goody four-hooves stuff.” Rainbow’s gaze immediately dropped to watch her friend’s hoof.

“What if I don’t want you to do that sort of stuff anymore?” Twilight asked, smiling as she saw the look of realization on Rainbow’s face.

“You mean?” The pegasus looked up at the alicorn, not quite believing what was coming out of the studious mare's mouth.

“You introduced me to a new side of myself, Rainbow Dash.” There was a seductive purr to the way she said her friend’s name. “A side that I kinda… like.” The purr was definitely there. “I’ve never thrown off the rules before, never just did whatever I wanted whenever I wanted, never not thought about the consequences. It was…” she looked down at the bed before looking up at Rainbow, "freeing.”

“You… enjoyed yesterday?” Rainbow asked, already suspecting the answer. “And you want to keep it going? With me?” There was a definite tone to the pegasus’s voice. The idea was ludicrous, and yet there was a pull, a desire, a want that could be heard in her voice.

Twilight nodded, her hoof once again sliding down the mare’s chest, stopping just above the line that would drive her crazy before making it’s way back up. “Oh sure, in public we’ll be the same as we’re supposed to be. You’ll still be part of the Wonderbolts, I’ll still be the Princess of Friendship.

“But no, I don’t want you to be miss goody four-hooves. I enjoyed yesterday a lot. And when it’s just us, I’d like it to stay that way. And… maybe sometimes when it’s not just us. But we’ll build up to stuff like that.” By the end of her statement the alicorn was definitely purring into Rainbow’s ear, causing the mare to coo in delight.

Twilight suddenly stopped her advancement, she then jumped off the bed and onto the floor. “Now, come on, my new pet’s gotta have a collar.”

Rainbow blinked her eyes three times. Each time she expected to wake up, or for Twilight to yell out ‘gotcha’ or something similar. It didn’t happen, at all.

“Oh, and I also think she needs her master’s mark, don’t you, Rainbow?”

“M-mark?” Rainbow asked, her eyes widening as she leaned forward to stare at her friend.

“Well, I got your cutie mark tattoo, I think you should get mine. Maybe on your back, right between your wings? I think that lovely mare at Stallion Cocks might be able to offer some suggestions about where to put it.”

Rainbow gulped. “Y-you’re… you’re serious?”

Twilight paused and looked back. “It’s the perfect excuse, no? We can say we got drunk last night and each got the other’s cutie mark as a tattoo. Sure, they’ll look at us strange, but once we say we’ve became marefriends, that’ll—”

“Marefriends?” Rainbow said, her tone pinching between terror, confusion, and something else.

“Well… unless you don’t want to,” Twilight said. “I mean, I know it’s the bet for you to do whatever I said, but I’d never force you to against your will.”

“I... have a choice?” Rainbow asked, her panic pausing to think about the situation.

“Of course, Rainbow. I had a choice in every action I took yesterday, I did it because I thought it’d help you. But… I think you helped me more than I helped you. There was something… freeing about doing what we did.” Twilight smiled dreamily, a shiver running through her body at the thought of ‘bucking the rules’.

“So, if I said no?” Rainbow asked, hesitantly.

Twilight paused, almost as if those words had physically struck her. “Well, you’d be welching on the bet, but I wouldn’t hold it against you.”

“I didn’t say no, I just asked what if I did say no. If I say yes, I’m basically going to be your pet though, huh?”

“Is that going to be an issue?”

Rainbow stayed quiet for a moment before looking up at the alicorn. She mumbled something, but it was too low for her friend to hear it. Can I really do something like this? Last night was fun, for sure, but… I mean… Rainbow’s thoughts were in turmoil, for the first time in her life she couldn’t decide if being “bad” was good or bad.

“What was that?”

“No, it’s not going to be an issue,” Rainbow huffed before hopping down off the bed and moving past Twilight to the doorway. I want to do this. A bet’s a bet and I’ve never welched on a bet before. Besides, I had fun with Twilight, plus not going to lie, the thought of being Princess Twilight Sparkle’s pet... it’s kinda hot.

“So you don’t mind being my pet?” Twilight asked with a grin, excitement shining in her violet eyes, almost intimidating the pegasus.

What am I getting myself into? Be cool Rainbow, it won’t be so bad right? The collar is kind of weird but I can do this.

“It’s the bet, right?” Rainbow asked, using that as her excuse. After last night, she had a new appreciation for the egghead that went well past her being a princess or a simple friend.

“Oh I’ve got some great ideas for us,” Twilight said with a chipper smile as she led the way out the door. “They had some whips and chains in that shop that Cadance said were a lot of fun! Oh, and we can also pay her a visit for some more… personal lessons.”

Rainbow chuckled, shaking her head but still smiling at her new marefriend. “It’s always the quiet ones.”

“But first we got to go visit that shop again and then get back to Ponyville as soon as possible. Oh, and you need to start writings those letters of apology to everypony in Ponyville. I’ll be checking over each and every one to make sure they’re heartfelt.”

“Ah, buck me!”

“Tonight, Rainbow, tonight.”

Dear Princess Celestia,

Something’s wrong with Twilight.

I can’t explain it but ever since your last visit a week ago, she’s been… well… she’s got a tattoo of Rainbow Dash’s cutie mark, she’s wearing a collar that says ‘bite me,’ and spending an awful lot of time around Rainbow Dash. Her friends and her got into a big fight where Twilight and Rainbow apologized profusely. In the end her friends forgave her, but…

I can’t describe it, I think I lack the words to describe it. In the last week I’ve made two checklists. TWO. I used to make at least twenty a day. She told me her and Rainbow have started dating and that’s how they ended up with each other’s cutie marks as tattoos, whatever that means, but… I’ve seen Rainbow with a collar now as well. And Twilight’s taken her... on walks.

Walks, yes, walks. Like a dog. There’s a leash and everything. And the strangest thing… Rainbow seems to enjoy it. Rainbow Dash, ‘The Rainbow Dash’, enjoying being led around like a pet!

I don’t know what’s going on here anymore! Twilight hasn’t freaked out once in the past week. A WEEK! Rainbow barely leaves the castle, and above all else they keep sending me on weird errands at odd hours. It’s like they want me out of the castle or something.

After the fight, they’re still cordial to their other friends, but it’s different. It’s like they are because they’re supposed to be, like they're keeping them at hooves length on purpose.

I suspect dark magic at work. VERY DARK MAGIC. Please come and save Twilight and Rainbow before anything else bad happens to them!

Sincerely, a very concerned, Spike the Dragon.

P.S. if you do decide to come I won’t tell them so you can see what’s going on for yourself.

With a quick lick of green flame the letter was off to Canterlot.

Spike worriedly tapped his claws together, his pacing of the crystal floor echoing around the castle of friendship. Before he could blink, a bright flash of golden light appeared not far from him, blinding him. It momentarily caused him to stop in his tracks.

Blinking back his surprise, Princess Celestia stood tall in front of him, her expression one of worry, but also stern.

“Where is Princess Twilight?” Her voice was soft but commanding at the same time, her eyes shining brightly in the dim light of the hallway.

Spike gulped back his fear, his thoughts rushing. Did I do the right thing by asking Celestia to come? Of course, Twilight and Rainbow need help and Twilight always said to ask for help when I need it. Princess Celestia is the best pony for the job. She’ll know what to do.

“She’s…”

Author's Notes:

Marry Xmas everyone!!!

Soo... who wants a sequel?