Pressing Matters with Sister

But something else was also happening. The previously mentioned precarious nature of the fly of my boxers meant that, as I humped into my sister's ass, my penis was starting to pop free. I could feel the fabric of my sister's panties tickle the skin of my dick with each press.

Lucy must have felt it too. She reached back with her hand, stopping our coupling. I thought, once again, that she was drawing the line.

Instead, she pulled her panties down her legs and tossed them off. She lay back down on her tummy.

"Lucy, are you sure?" I asked. The argument roiled inside me; I could almost picture a chivalrous knight fighting a crazed barbarian. A funny metaphor for what I was feeling. And I'm sure you can figure out who was winning.

My sister tapped her headphones, as if to say that she couldn't hear me over her music. I supposed that was my answer. I took off my own underwear. Both of us were now naked from the waist down. I lay down on top of my sister. My cock nestled in that most precarious of places.

Bare skin to bare skin. I could feel the heat of her pussy, emanating out like a tiny sun. My hardness against her soft, wet spot. I didn't need to move; this was already beyond anything I'd ever felt.

But I did move. I pressed down. Lucy rubbed up at the same time. The two of us groaned in unison. We didn't need words. We humped against each other. Totally connected. Well, almost totally. Our bodies decided to fix that distinction for us.

The first time, the head of my penis grazed my sister's pussy so slightly, I hardly noticed.

The second time, my dick actually held for a moment, right at the entry to Lucy's pussy, before slipping away.

The third time, my cock actually went inside. No more than an inch. Barely the head of my head. And yet.

Both of us froze there. Right on the precipice of penetrative sex. I waited for my sister to tell me 'no.' I waited for my own conscience to cry out. None of that happened.

I pushed forward a little further. My older sister lifted her hips to ease my passage. My head snuck in. Halfway down my shaft. I pulled back. Thrust again. Lucy grunted. Finally, I was fully buried inside my sister's body.

For the first time since the process started, Lucy turned and looked back at me. Her expression was unreadable -- a mix of total joy and absolute concern. Fear, desire, sadness, exultation. All in one. I was feeling it too.

I drew back slightly, then pushed forward. My sister's face twisted as the sensation overtook her. Eyes rolled back. Lips curled. She turned forward, resting her head on her arms.

We rolled against each other. Together, truly, for the first time. I heard Lucy make all those familiar noises I'd known from before -- the little gasps and groans. Squeaks and mewls. But now they were coming because of me.

"So good," she gasped.

I couldn't respond, already wrapped up in my own pleasure. The heat of my sister's pussy, her warmth and wetness, it was like nothing I'd ever experienced. Amplifying everything from simple sex to something beyond what we have words for. Intimate beyond intimacy.

I was fucking my sister. I couldn't get past that fact. It was integral to the experience. The wrongness of what we were doing. The rightness of it. Everything about the physical act was overwhelmed by the emotional part of it.

I reached my hands down and found my sister's amazing breasts. Over her shirt, was still more than enough. I squeezed those massive mounds, using them like handholds, as I humped my sister from behind. I didn't ever want this to end.

"Getting... close," Lucy said. Her voice strained. God, I wanted her to cum so bad. But her words had a secondary effect.

"Me too," I said. I was very aware, then, of what we were doing. Had done. The consequences racing towards me, but I couldn't look away.

"Don't stop," Lucy said.

Our movements became frenzied. Moving in synchronicity; racing in opposite directions -- Lucy trying frantically to reach her orgasm, me trying desperately to escape mine.

"Don't stop," Lucy said it again. "Don't you dare stop."

"Trying..."

Lucy's body undulated under me. Even though I was on top, she was clearly in control. She arched and shimmied. Rubbed and cinched. Moved her body on my cock like I was only an object. Faster. Faster.

Finally, she stopped. Stilled.

"Ohhhhh" the word slipped out of her like steam. Pitch rising till it left my spectrum.

I'd seen Lucy's orgasm so many times, I could replay it in detail on the back of my eyelids. Heard it so often, I could write it as a symphony. Even smelled it, her femininity filling my nostrils as she flooded.

But I'd never felt my sister's cum before.

Her pussy clamped down, sealing shut like it was one of those vacuum storage bags. Air tight. Her butt slammed downward. Her back arched. We don't need to invent a cock-milking machine. My sister already has the perfect one built in.

"Lucy, I'm..." My inner knight took one final, desperate swing.

"Dooooon't. Stooooop," Lucy said, a low deep rumble I could barely make out.

It didn't matter what she'd said. It was already too late. The pleasant tingle in my penis turned into a spark, racing fire down my shaft and straight into my sister's unprotected pussy.

I let out a long, strangled cry. A river of sperm burst into my sister's snatch, while an ocean of illicit bliss rolled over my body. I jammed my dick as deep as it would go. Squeezed Lucy's breasts so hard, there would be bruises after. Pressed as hard as I could as plume after plume of pleasure arced out of me.

Vaguely, I was aware of the sister beneath me, enduring her own ecstasy. She told me after, feeling my hot cum splash against her cervix had triggered a chain reaction, taking her already extant orgasm and exacerbating it. Like pumping gasoline into a fire.

Lucy burst. Her brain blew out. Her body shivered and shook. Wordless, primal sounds escaped her lips. She came like she was crazed by it. Like I'd unlocked the higher function of her pleasure centers. Both of us awash in the chemicals of reproduction. Oxytocin and dopamine. Endorphins and adrenaline.

My cock finally gave up trying to find more cum to pump into my sister's fertile pussy. It didn't shrink, so much as it lay down, exhausted. Lucy's body went limp. I fell with her. Her soft skin felt almost too hot. We rolled off each other, sweaty.

"Oh fuck," Lucy said. I couldn't tell if it was in celebration or regret. Maybe a bit of both.

She rolled over and sat up. Absently, she dipped her fingers in her pussy. They came out covered in white goop.

"Oh fuck," she said it again. "Oh, fuck me."

Reality raced over me. That post-cum rationality burst forth. What we did. What we'd done. Whatever post-sex satisfaction I had earned was obliterated by guilt. I'd just had sex with my sister. Committed incest. Inseminated her unprotected pussy. All of it. My most forbidden dream. My totally enrapturing nightmare.

"Lucy, I'm sorry," I said, "I didn't mean to." My apology felt so stupid in my own mouth, I couldn't imagine how idiotic I sounded to my sister.

Lucy didn't say anything. She rolled over and held me tight, like cradling a crying baby. Her bare bottom pressed against mine. I felt a stream of my own semen drip out of her pussy and land, warm, on my thigh. The tickle of her pubic hair on my rapidly shrinking cock.

"It's OK," Lucy said, shushing me. "It's alright."

We stayed like that, half naked in her bedroom, holding each other close for as long as we could. Neither of us knowing what to say. What to do.

Staring down a suddenly very uncertain future.