Ben and Susan’s unusual relation – part 4

“What are you doing down there?” she asked.

“What do you think?”

I ran my fingers up the inside of Susan’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,” Susan 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. Susan 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.

Susan’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,” Susan 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.

Susan 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.

Susan’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 too loud cry, at least to my ears, Susan 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 alright in there?” came a voice from outside.

“Yes thanks,” Susan called back without missing a beat. “Almost done.”

“Okay,” the voice replied uncertainty.

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

“Well that was fun,” Susan 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,” Susan apologized. “I will later, I promise. You more than earned it today.”

“Strangely that doesn’t really help me right now,” I said.

Susan 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 into 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 was distracted by another customer. At least I assumed it was her, there weren’t any other suitable candidates around.

Humming cheerfully to herself Susan 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 to make an issue of it and I’d started to relax. Susan 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,” Susan 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 Susan, 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 into 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. If 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 Susan 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 Ray’s class with nothing going wrong and finding Susan there waiting for me. Sherin was with her actually, the two of them deep in conversation until I stepped through the doorway.

“Want to lock that behind you?” Susan said.

“Sure,” I said.

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

“I told Sherin she could stay if she wanted,” Susan said. “You don’t mind too much do you?”

“Uh, no, that’s fine,” I said.

“Good, ’cause we still owe her for helping us.”

The trail of logic on that one was a little difficult to follow. As I recalled Sherin 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.

Susan 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 Sherin 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,” Susan 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 Susan’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.”

Susan 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 sizable 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.”

Susan’s 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 with each other for a minute or two before Susan 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. Susan 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 Susan’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.