Because We're Bad Ch. 02

There wasn't a lot of space with both of us inside, but it wasn't too cramped either. Kristin was standing in front of the mirror examining the skirt she had put on critically. I thought she looked hot in it, but didn't have much of an opinion otherwise. Plus I thought she looked hot in most anything.

"It's fine," I said.

"You don't think it's too long? I didn't want to go too short and get in trouble, just keep it at the right length."

The bottom of the skirt came down to maybe a couple inches above her knees and I knew that given our school policy she wasn't going to get away with much more than that.

"You look great," I insisted.

"Wouldn't matter what I had on you'd still say that, don't know why I bother sometimes," she said.

"Because you like hearing me tell you how good you look probably."

"Oh yeah, that's it." She giggled. "I guess if I really wanted compliments I'd go a step further."

In one deliberate, smooth motion Kristin pulled the skirt down to her ankles and stepped out of it. Underneath she was wearing one of the pairs of panties we'd picked out, and it was just as useless at properly covering her as I'd hoped. From behind the panties did little more than draw a nice dividing line down the middle of her ass, and when she turned around I saw that they weren't doing much better in front. Her pussy was barely covered and if she had any hair down there it would be clearly showing around the edges of the material.

"I'm guessing you like them," she said.

"Uh, yeah."

"Even though they're really, really small in the back?"

As if that was a downside for me.

Kristin took my hand and pulled it around to her lower back, then down to the top of her butt.

"I bet they're just gonna ride up on me and disappear, hardly even worth wearing them," she said.

I ran my finger down the centre of her ass, pressing the panties between her butt cheeks.

"You might be right," I said.

"Uh huh, but I know you don't really care do you? You'd like it if I didn't wear any underwear."

"I might."

As I continued running my finger up and down the line of her panties, pushing them as deep as I could, I encountered something I didn't expect. There was something there, something that seemed very deliberately placed, and I could tell that Kristin had been waiting for me to find it.

"Is that..." I started.

"A butt plug, yeah," she confirmed. "I got it after we talked about you fucking me back there. Actually I got two, the other one's a little bigger for when I get used to this one. I think I'm almost ready 'cause I sometimes forget I even have this one still in. Told you I'd work on it."

"And you were wearing it all day?"

"Yep. Had to get off in the bathroom at lunch when I got too horny, but it's totally worth it. Feels good when I play with it too."

A shiver went down my spine as I imagined my sister playing with herself and her new toy. I had already been pressing on the butt plug experimentally, but at her encouragement I wiggled it more purposefully making her gasp softly.

"How did it take me so long to figure out sexy you were?" I asked, not expecting a real answer.

"Because I never had any reason to be sexy for you before," she said. "Now I do. And I think I'm doing a pretty good job."

"God, are you ever."

While I played with Kristin's butt she started grinding slowly on my leg, pressing her body firmly against me. I enjoyed the feeling, but there was an immediate problem to be dealt with if things continued the way they were going.

"You're going to get those panties all wet if you keep that up," I said.

"So? I'm gonna buy them anyway."

"That's fine, but I'm refusing to be seen with you if you set those on the counter soaked and smelling like sex."

Kristin pouted but offered no real objection, particularly when I knelt down in front of her and started pulling the panties down. I brought them up to my face after she stepped out of them and examined the material closely. There was already a small damp spot, but fortunately nothing overly noticeable if you weren't specifically looking for it.

As I set the panties aside I was left kneeling in front of my half-naked sister with her bare pussy directly in front of me. I knew it was an incredibly stupid place for us to risk getting caught, all someone would have to do was open the door and we'd have nowhere to hide. In theory the door was locked, but it wasn't the sort of lock I would trust with anything important. It was just enough to make people feel comfortable trying on other clothes in a somewhat public location. On the other hand Kristin's perfectly smooth pussy was not something I could pass up easily when it was right there in front of me, begging to be touched.

"What you doing down there?" she asked.

"What do you think?"

I ran my fingers up the inside of Kristin's thigh and over her pussy lips, parting them slightly as I did. I gave the length of her slit a preliminary lick and once more experienced the unique taste of my sister, a taste that I absolutely loved.

"You know if I tried stripping you and giving you head in here you'd freak out on me," Kristin said.

"Probably," I agreed. "You want me to stop?"

"Uh uh, no way."

"Good, then stop pointing out my hypocrisy because I'm well aware of it without your help."

I tried to be careful and stay out of trouble, and usually I succeeded pretty well. Kristin was a massive weakness for me in that regard however, I couldn't always do the sensible thing when I was with her. It had always been that way and the effect had only gotten worse recently. Sure I could still maintain control if I really wanted to, but the truth was that more and more I was prepared to choose my sister over any kind of reason or logic.

Kristin's fingers tangled in my hair as I licked repeatedly at her pussy and her legs parted eagerly at my slightest touch. There were other people out there walking by as close as a few feet away, yet I was going to make her cum. It was going to happen. It was one of those rare times when I felt as though I could understand how her world worked, when consequences were meaningless and all that mattered was what I wanted at that moment.

"Mmm, I love it when you get like this," Kristin said. "Everyone thinks you're such a good boy, but you're not really are you?"

I don't know if she expected me to argue the point, but all I did was ignore it. I had more important things to think about, things which would severely undercut any protest I might make to her claim.

Kristin made an appreciative noise as I pushed a finger inside her increasingly wet pussy with a second one close behind. She let me finger-fuck her for a little while before regaining her train of thought.

"What would people think if they knew you as well as I do?" she mused. "Come to think of it, what if they knew just how bad I was too? We'd be grounded forever just for a start."

She giggled at the thought, then abruptly gasped as I used my remaining free hand to find the butt plug she was still wearing. I already knew she liked me playing with it, but I hadn't realized just how much it could affect her when combined with the stimulation on her pussy.

"Oh fuck, keep doing that," she breathed.

Kristin's hips bucked against my face, threatening to dislodge me and making my job significantly more difficult. I knew she was getting close though and I didn't give up, instead responding with more force of my own. I licked furiously at her clit and increased the pace of my fingers inside her until finally she had enough.

With an all to loud cry, at least to my ears, Kristin fell back against the wall as her pussy clamped down firmly on my fingers. I kept licking as she came, only stopping when it was obvious she was through. As I looked up at her in the aftermath her more familiar look of mischief and lust was replaced temporarily by an expression of sated contentment.

The moment was quickly ruined by a knock on the door, making me panic at the returning realization that we weren't exactly somewhere private.

"Are you all right in there?" came a voice from outside.

"Yes thanks," Kristin called back without missing a beat. "Almost done."

"Okay," the voice replied uncertainly.

After a moment I heard footsteps walking away and my shoulders sagged in relief. That was too close.

"Well that was fun," Kristin said.

She bent over and kissed me, evidently not caring that I tasted like her pussy. I felt a twinge of regret as she started getting dressed even though I knew that we had to go or risk attracting more attention. My cock was straining in my pants and part of me wanted nothing more than to pin my sister against the wall and fuck her. Having self-control sucked sometimes.

"Sorry I can't take care of you too," Kristin apologized. "I will later I promise. You more than earned it today."

"Strangely that doesn't really help me right now," I said.

Kristin shrugged and unlocked the door.

"Shall we?" she asked.

She didn't wait for an answer and before I was truly ready I was following her back in to the store proper. My erection had settled down a little, but I was worried it would still be noticeable if someone got too close. Luckily no one was nearby, even the sales girl who almost caught us has been distracted by another customer. At least I assumed it was her, there weren't any other suitable candidates around.

Humming cheerfully to herself Kristin approached the counter to pay for her choice of skirt and panties while I skulked around nearby, trying to watch every direction without making it obvious. By the time we made it out of there I had decided that no one was curious enough about what we'd been up to that they were going make an issue of it and I'd started to relax. Kristin didn't look at all concerned about it the whole time, but I'd come to expect that from her. She had way more practice at acting normal than I did.

"We should do that again some time," Kristin said as we headed back to the car.

"I wouldn't count on it," I said.

"Yeah yeah, you say that now. I could get you back there right now if I really wanted to."

She was probably right, especially given how horny I still was.

"How about we don't test that, okay?" I said.

"Nah, I wouldn't. Maybe if I was bored enough, but I've still got Friday to look forward to."

****

The day couldn't come soon enough for Kristin, as short a time as it was in reality. I watched her get dressed in the morning, as I liked to do when I had the opportunity, and she put far more effort in to her appearance than normal. With her skirt, a white button-up blouse, and her hair pulled back into a ponytail she looked far more like the archetypal schoolgirl than I'd ever seen her before. It only she could have masked the wicked glint in her eyes the image would have been perfect.

I will admit to a certain amount of anticipation throughout the first part of the day. Having sex with Kristin wasn't ever going to be something I would dread, even if the circumstances weren't ideal in my mind. Plus she actually looked really hot in her outfit, in a weird, subtle kind of way since it wasn't overtly any more sexual than something she would wear normally.

By the time fourth period rolled around I was having trouble acting casual and I was sure someone was going to notice that I was behaving oddly. It was a bit of a relief to finally make it to Miss Reid's class with nothing going wrong and finding Kristin there waiting for me. Shannon was with her actually, the two of them deep in conversation until I stepped through the doorway.

"Want to lock that behind you?" Kristin said.

"Sure," I said.

With the door locked we were reasonably secure inside the classroom and either Kristin or Shannon had already pulled the curtains across the windows so no one could see in from outside.

"I told Shannon she could stay if she wanted," Kristin said. "You don't mind too much do you?"

"Uh, no that's fine," I said.

"Good, 'cause we do still owe her for helping us."

The trail of logic on that one was a little difficult to follow. As I recalled Shannon was supposed to be making sure no one interrupted us, which she couldn't very well do if she was watching us. On the other hand having her out in the hallway would hardly be inconspicuous. Fortunately the deal was between my sister and her friend and if it didn't make sense to me it wasn't a big deal.

Kristin stood beside the teacher's desk at the front of the room with her hands clasped behind her back and her chest sticking out slightly. As I approached her Shannon stepped to the side and sat on the edge of one of the tables in the front row.

"See, I knew you didn't really hate this idea," Kristin said as I placed my hands on either side of her waist.

"I rarely hate your ideas, I just don't always think they'll work out," I said. "This time you actually put some thought into it."

I stopped Kristin's response by kissing her, pulling her closer to me as I did. I didn't want to antagonize her enough that she'd up the stakes on me.

My hands slid easily underneath her shirt as we held each other and rested comfortably on the bare skin underneath. I slowly moved one of them upward, over her tummy and not quite reaching her breasts before she pulled away a little.

"Mmm, getting kinda horny now," she said.

"Aren't you always?" I said.

"More than usual then. Here, you can probably feel it."

Kristin took hold of one of my wrists and guided my hand under her skirt to the front of her panties. As I pressed my palm against them I could feel a sizeable damp spot already formed.

"Jesus, we barely even did anything yet," I said.

"I know, but you remember how I said I had another butt plug that's a little bigger? Well I've been wearing it all day and it's been turning me on like crazy. It feels even better than the other one. I think I'm ready for you now, for real this time."

Kristin hips rocked gently on my hand almost of their own volition, and when I pressed back against her pussy she moaned softly. She was definitely worked up already, there was no question about it.

With slightly shaky hands she undid the front of my pants and reached in to grasp my hardening cock. She gave a gentle squeeze and stroked her fingers across the length of my shaft as I continued rubbing her wet panties.

We stood together essentially masturbating each other for a minute or two before Kristin backed away and leaned over the teacher's desk, bracing herself on her arms. She turned her head back to look at me in a silent invitation that I could hardly refuse.

I moved behind her and slid my hands up the outside of her thighs under her skirt, not yet lifting it quite high enough to expose her butt. It was simple enough locating the waistband of her panties by touch and tugging them down to her knees. Kristin let them fall to the floor and carefully stepped out of them, kicking them unceremoniously to the side.

With her panties out of the way I pulled Kristin's skirt up around her waist to reveal her bare ass. I was intimately familiar with this part of her body, except for right in the middle was the black, circular base that was all I could see of the butt plug currently inside her. All I could do for a long moment was stare at the expected yet fascinating sight, too long for my sister.

"Come on, what are you waiting for?" she demanded. "You need instructions back there?"

"Just looking," I said.

To pacify her a little I pressed my fully-hard erection against her pussy, making her sigh happily. She began rocking back and forth in small movements, but didn't have the right positioning to get me inside her without help. Before she got impatient again I guided my cock to her entrance and allowed the motion of her hips to slowly impale her on my shaft. Once I got her started she did all the work and I didn't even have to move.

I heard a sound from behind me and turned my head just enough to glance at Shannon who I had almost forgotten was there. The front of her pants was open and her hand was buried under her panties, masturbating freely at the show Kristin and I were giving her. I'd expected it to happen as she got more comfortable around us, although she was a bit quicker about it than I would have predicted. She met my gaze for a second as I looked at her and seemed embarrassed, but didn't stop what she was doing.

Kristin continued fucking herself on me as I turned back to her, although she faltered slightly as I grabbed the base of her butt plug. As I had done back in the clothing store I merely played with it at first, wiggling it around just to see what kind of reaction I got. My sister had a different idea of what I should be doing.

"You're gonna do it aren't you?" she said. "You're gonna fuck me back there."

"Do you want me to?"

"Duh, that was the whole point of getting ready for you. You think it was just for fun? Actually, it was kind of fun when I think about it."

Kristin giggled softly to herself as I decided on my course of action. It wasn't really a difficult choice when it came down to it, it just seemed like our first time trying anal should have been somewhere a little more traditional. Like in a bedroom.

I pulled on the base of the butt plug, slowly fighting against the resistance Kristin's ass put up trying to keep it in. As the widest part made it past her outer ring she moaned and stiffened up while her pussy squeezed my cock hard. Once I had the butt plug out I waited for Kristin to recover a little before trying anything else. Even after her pussy relaxed it was a couple minutes before she straightened back up to her initial stance.

"You still want me to do it?" I asked softly. "That seemed pretty intense."

"It was kinda," Kristin said. "It's just so... bad having my brother playing with my butt like that. I love it. Although I think if you're not in my pussy at the same time it won't be so much for me and I could handle it better."

"Okay, but you have to tell me if it hurts or if you want me to stop for any reason alright?"

"Promise."

Kristin's asshole was still lubricated from where she'd put in the butt plug and my cock was covered in her pussy juice. I thought about asking if she had more lube with her just in case, but decided to at least try it first and see how easily it went. It wouldn't be completely new to her this time so it might be okay.

I placed the tip of my cock directly against my sister's anal opening and pressed gently, but with gradually increasing force. She pushed back and slowly her asshole reopened for me and let me in. As soon as the head of my cock popped inside her ass she froze and I immediately stopped moving as well. A small growl of pleasure emerged from her and her back arched as far as it would go.

"You still okay?" I asked.

"Fuck yes, this is amazing. Don't you dare stop."

She started rocking back against me, not enough to really drive me any farther into her but just to encourage me to keep going. That was all it took for me since already the feeling of being in my sister's ass was incredible and my instincts were urging me to start fucking her for real.

I couldn't go as fast as I was used to with her pussy of course, her ass was tighter and despite what she was telling me I knew she still wouldn't be ready for anything too rough back there. On the other hand I probably wouldn't last that long even going slowly, not if it continued to feel as awesome as it did.

Alert for any sign of discomfort I thrust my hips forward, pushing a little deeper into Kristin's ass. Unlike regular sex I found my movements had to be more purposeful, more controlled, but it was worth the effort.

"Shit, gonna cum again," Kristin mumbled.

"What already?"

My cock was only a little over halfway inside her, maybe two-thirds at the most, and I hadn't even started to properly fuck her yet. As she had warned me though she was soon cumming again, collapsing forward onto the desk as her orgasm drained the strength from her arms.