I slammed the car door shut and my stepmom, Lisa, was already climbing into the backseat with me, her short skirt riding up her thick thighs. "Your dad and your sister are passed out up front," she whispered, voice low and filthy. "We got twenty minutes before the next rest stop. Get that cock out."
I didn't need telling twice. My dick was already hard from the way she'd been teasing me all day at the family reunion, brushing her big tits against me every chance she got. I unzipped, pulled it free, and Lisa's hand wrapped around it right away, stroking slow and tight. "Fuck, you're throbbing," she muttered, leaning in to spit on the head before jerking me faster. "Been wanting this since we left the house."
Up front, my dad snored and my stepsister had her headphones on, dead to the world. Lisa hiked her skirt higher, no panties underneath, and swung one leg over me. She sank down on my cock in one smooth move, her wet pussy swallowing every inch. "Goddamn, that's deep," she groaned, starting to ride me with short, dirty bounces that made the car creak.
I grabbed her ass with both hands and thrust up to meet her, the wet slap of skin loud in the quiet car. "Ride it harder, Lisa. Fuck yourself on me." She did, grinding her clit against my base every time she bottomed out. Her tits spilled out of her top when I yanked it down, and I sucked a nipple into my mouth, biting just enough to make her gasp.
She reached back and grabbed the headrest, using it for leverage as she bounced faster. "Your dad's right there and I'm creaming all over his son's dick," she hissed. "Feels so fucking wrong and so good." I could feel how soaked she was, her juices running down my balls onto the seat. Every thrust made a filthy squelch.
I flipped her onto her back across the bench, hiking one of her legs over my shoulder. I pounded into her deep, the car rocking with the motion. Lisa bit her lip to stay quiet but little moans still slipped out. "Harder," she begged. "Split me open." I gave it to her, slamming balls-deep, watching her tits bounce with every thrust.
She reached down to rub her clit in quick circles while I fucked her. "Gonna come," she warned, and her pussy clamped down tight, pulsing around my cock. I kept driving through it until she shuddered and went limp for a second. Then I pulled out, flipped her onto her knees facing the window, and shoved back in from behind.
The new angle let me hit her G-spot. Lisa pushed back against me, meeting every stroke. "Use me," she said. "Fill this married cunt." I gripped her hips and railed her, the wet sounds and the slap of my hips on her ass filling the car. Up front nobody stirred.
I felt my balls tighten. "Gonna nut," I grunted. Lisa reached back and spread her ass cheeks wider. "Do it inside. Pump me full." I buried myself to the hilt and unloaded, thick ropes of cum shooting deep into her pussy. She moaned low and kept squeezing me, milking every drop.
We stayed locked together for a minute, breathing hard, cum leaking out around my cock. Then she eased off, pulled her skirt down, and wiped her thighs with a napkin from the door pocket. "Next rest stop," she said with a smirk, "your turn to drive and mine to suck you clean."
I tucked myself away, heart still pounding. The family car smelled like sex and we still had hours to go.
