I slammed the car door shut behind me and slid across the backseat, already knowing this drive home was gonna end with my cock buried in my stepsister's tight cunt. Rachel was nineteen, legal as fuck, all long legs and perky tits that bounced under her thin tank top. I was twenty-one, and we'd been eye-fucking each other for months while our parents pretended not to notice the tension.
The family minivan pulled out of the rest stop parking lot. Mom and Dad were up front, headphones in, zoned out for the long night drive. Rachel climbed in after me, her short skirt riding up to show the edge of her white panties. She didn't fix it. Instead she smirked and spread her thighs just enough for me to see the damp spot growing there.
"Drive safe, Dad," she called out, voice all sweet and innocent. Then she leaned over and whispered in my ear, "I'm so fucking wet already. Been thinking about your dick all day."
My cock twitched hard in my jeans. I reached over and grabbed her thigh, fingers digging in. "Shut the fuck up before they hear," I growled low. But I didn't stop her when her hand slid straight to my zipper and yanked it down. She pulled my thick cock out, already leaking precum, and wrapped her fingers around it.
"Jesus, it's so big," she muttered, stroking slow and dirty. Her thumb smeared the head, making it slick. I bit back a groan and shoved two fingers under her panties, finding her shaved pussy dripping. I pushed inside her without warning, and she clenched around me, hips rocking.
We kept it quiet at first.
The road hummed under the tires while I finger-fucked her slow, curling to hit that spot that made her bite her lip bloody. Rachel pumped my cock faster, her other hand cupping my balls. "I want you to fuck me right here," she hissed. "Right in the backseat like the dirty incest slut I am."
That was all it took. I yanked her panties aside, pulled her onto my lap facing me, and slammed my cock up into her soaked cunt in one thrust. She was tight as hell, gripping me like a vice. Rachel gasped but stayed silent, burying her face in my neck as she started riding me. The car rocked just a little with every bounce of her ass.
"Fuck, sis," I grunted against her ear. "Your pussy feels better than Mom's ever could." The taboo words made her clench harder. She ground down, taking every inch, her clit rubbing against my base. Her juices ran down my shaft onto my balls, soaking my jeans.
We moved like animals trying not to get caught. Short, hard thrusts upward while she circled her hips. Her tits pressed against my chest, nipples hard through the fabric. I reached under her skirt and squeezed her ass cheeks, spreading them so I could feel my cock stretching her hole every time she dropped down.
"Don't stop," she whispered, voice shaking. "Fill your little sister's cunt. Breed me right here while they drive."
I grabbed her hips and took over, pounding up into her fast and filthy. The wet slap of skin on skin was barely covered by the engine noise. Rachel's pussy fluttered, getting ready to come. I shoved a finger against her asshole, pressing just enough to tip her over. She came hard, biting my shoulder to muffle the moan, her walls milking my cock in hot pulses.
I didn't last long after that. I buried myself balls-deep and unloaded, pumping thick ropes of cum straight into her womb. It leaked out around my shaft, messy and hot, dripping onto the seat. Rachel kept grinding through it, squeezing every drop out of me.
We stayed locked together for a minute, breathing hard, cum and pussy juice making everything slick between us. Then she climbed off, licked my softening cock clean with her tongue, and pulled her panties back into place like nothing happened. The wet spot on the seat was our little secret.
By the time we got home, my cum was still leaking down her thighs. She winked at me before heading inside. We both knew the next car ride would be even dirtier.
