We Need to Study Our Math Ch. 04

Soon, she was wiggling, moaning, writhing under my tongue's touch. I could feel her passion rise in response to my touch; my own passion rose in concert with hers. My cock, confined in my jeans, was painfully stiff, and—while continuing to stroke and taste her intimate parts—I reached down with both hands and undid the fastenings of my own jeans.

My boner needed freedom, and I accommodated it by lowering my jeans to my knees. The cool outer air on it exacerbated my need to embed it in something warm; I withdrew my tongue from her cleft and looked up at her face. "God," I said, "I need you."

She looked back at me, her face contorted with her own lust, and said, "I need you, too. I wish we could..."

I rose and stood over her. As I did so, my pants slid down my legs to my ankles, so that my cock extended into the cool room air where she could see it. She looked hungrily—reflecting the hunger her pussy had generated in me. I imagined its tight, wet, warm clasp on my cock, and I longed for that.

"You're breaking the Pants Rule," she said.

There was no reproach in her voice; she was just making an observation. Realizing that, I replied, huskily, "That's not the only rule I'm going to break." And I reached down to grasp my cock, stepping toward her as I did.

Seeing my intent, she said, "No, Mase. We can't do that. You know we can't. We agreed!"

Echoing her words on an earlier occasion, I replied, "We can change the agreement."

"We shouldn't," she answered. But there was more to her answer, because as she spoke, she drew her knees up toward her shoulders, spreading her thighs as she did so—opening her pussy to my approaching cock.

"Just..." I began, and hesitated, both in speech and in motion. "Just one more time," I said. "Just this once." And I began to move again, slowly and carefully forward, giving her every chance to stop me.

I lowered myself, directing the tip of my hard-on toward the opening that lay, not quite concealed, in her cleft; I felt the hot moist kiss of her pussy's entrance as we made contact. She looked directly into my eyes, making no effort to fend me off or even to redirect me. "We really shouldn't...," she said, weakly. Her resolve to resist me was weak, non-existent; she wanted what I wanted, I understood, probably as much as I did.

I could wait no longer to see if she would stop me; I pressed forward and my cock forged into her welcoming clasp. Once again, I experienced the ineffable sensation of her flesh stretching to accommodate me as I slid into her. She closed her eyes and exhaled in a long sigh. It was, I thought, an acknowledgement of her need for we were now giving each other.

We rested there for a moment, her brother's cock fully embedded in his sister's pussy, our bodies adjusting to their union. We looked into each other's eyes, gathering for the upheavals we knew were now assured. "This is so wrong," she whispered. Her hips moved under me, rocking to cause her sheath to deliver a welcoming stroke to the rod I'd planted in it. And, as my own hips began to respond to her motion, she added, "...and so wonderful!"

Slowly, I pulled back, savoring the friction between her sheath and my cock as I glided out of her. I pulled back until my tip barely remained inside her, and then I reversed my motion to push myself—just as slowly—back into her depths. When I was as deep in her body as possible, I waited a second and then did it again.

"That's so good!" she whispered. "How long is that thing?" She looked downward to see the full length of my cock as I slowly withdrew most of it from her body and then slowly reentered her. "You make it feel like it's a yard long!"

I said nothing; fucking her slowly required all my concentration; I had no capacity left for speech. Still looking into my eyes, she began moving her own hips in rhythm with mine, and I felt the pressure building in my groin. The fires of excitement and desire coalesced in my groin as, enthralled by mounting sensation, now, we increased our pace.

In and out, I drove my cock faster and faster; she responded, meeting my thrusts with her own motions. Desire mounted in her, too. In growing anticipation, we pounded against each other, staring all the while into each other's eyes. Quickly, more quickly, we drove ourselves until, together, we exploded in our mutual climax. Cum—her twin brother's cum, my cum—surged into her, surged again, and again, into her seething pussy. In the throes of my orgasm, my feet lost their purchase on the floor and I collapsed into her arms. Her body went limp under me as her own culmination passed.

We lay there in each other's arms, our bodies resting against each other, my still stiff cock deep in my sister. Her internal muscles alternately contracted and relaxed around me.

An indefinite time passed, and I pulled my softening cock out of her. Rolling and turning, I stretched out beside her. Again, I felt the coolness of the air surrounding my cock—coolness enhanced by the mixture of our emissions that covered it.

Languidly, she pulled her own body up on to the bed, turning it to lie beside me, her head on my shoulder. I extended my arm and wrapped it around her, pulling her more tightly against myself. She rolled toward me, bringing her body to rest against mine. We lay there, enjoying the lazy aftermath of our exertions and the quiescent touch of our naked bodies against each other.

"You're still a good fuck," she whispered in my ear.

"You're the best piece of ass I've ever had," I whispered back.

We lay there in silence for a minute or two. Then: "We weren't going to do that," she said.

"No," I agreed. "We weren't."

"But we did."

"We did."

"I think I'm glad," she said.

"Me, too," I answered. "It's just too bad..." I let the sentence hang.

She finished it for me: "...that we're twins."

"Yeah."

Another minute of silence.

"How long has it been since they left?" she asked. I was between her and the clock.

I looked over and replied, "About twenty-five minutes," I said. "We still have at least a half hour till they get home." They probably wouldn't come upstairs again that afternoon, and certainly not right after they got home, because they'd be putting groceries away in the kitchen. But they'd expect us to help with that chore, so it wouldn't be a very good idea for us to be lying in bed together, naked, when they arrived.

"Good," she said. "We can relax for a little while."

We did so, lying on my bed, bodies against each other, simply enjoying.

"You felt so long inside me," she said after a few minutes had passed, rising to look at my limp cock.

"I think I'm about average size," I said. "But it won't do you much good to look now," I said. "You made it get short again."

She got to her knees beside me. She gave me her sly smile and said, "Let's see if I can do something about that." And she bent over toward me; using one hand she guided my slippery limp cock into her mouth. Under the action of her lips and tongue, it wasn't long before I'd swelled again to full hardness.

She slipped my cock out of her mouth, and looked at it. "I think it's just the right size," she said. "It sure did feel good inside me. I like it." She paused to study the object of discussion. Then she threw her leg over me and knelt above my hips, facing me. "I like it so much," she said, "that I'm going to fuck you again." And she lowered her body, directing my now fully hard cock into herself as she did.

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"What're we gonna do?" she asked, as she stroked my chest. We were lying relaxed, again, on my bed, naked body against naked body, after the second storm of the afternoon had passed.

"I hope we're gonna do that again," I said.

"We can't," she replied. "We can't keep doing this with each other." There was a tinge of regret in her voice.

I had growing doubts about that, but now didn't seem like the time to voice them. "Well," I said, "one thing we'd better do—right now—is get off this bed and get dressed before Mom and Dad get home."

She looked at the clock as we rolled out of opposite sides of the bed. "They shouldn't be home for at least another ten minutes," she said. "But let's not take any more chances than we have to."

That was something I could agree to, even though we now seemed to be in the business of taking chances we didn't have to. I didn't think it was the right time for making that observation, either.