Covering quickly, even as I kept fucking her, she answered, "Just got a text that Sarah finally dumped that loser Jake."
"Oh, okay," Mom said.
For a couple of minutes, I fucked her as best I could in the awkward position I was in.
It felt so amazing, yet I couldn't get into a rhythm.
She then sat down on my lap and began riding me.
I groaned as she began bouncing on my dick, the sounds of our bodies colliding covered by the radio and the loud sounds of gravel underneath the car.
My balls began boiling, and it was clear Quinn was getting close. She was biting her lips.
Her eyes were closed.
And she was riding me as fast as she could as she again grabbed onto Dad's chair.
"You okay, honey?" Dad asked, feeling his chair pulled back.
"Never better," she answered.
"Only about thirty minutes left," he said.
"Okayyyyy," she replied, her orgasm close, another bump on the road able to hide the real intent of her moan.
"Sorry," Dad said.
"Oh, I'm getting used to being bounced around," she quipped, which made me gasp slightly at the wicked double entendre.
"I'm sorry," Dad said.
Mom offered, "I could replace you back there, Quinn."
I smirked at the reality of what Mom was unknowingly offering.
"I'm not sure you could handle the pounding I'm taking back here," Quinn replied, as she slammed down, looking back at me with a wicked smile.
Oh fuck! God, my sister was wickedly hot.
"You sure?" Mom asked. "I don't mind the bumps." "It's okay, Mom. I'm finally in the perfect position."
"Me too," I added.
"Okay," Mom said. "But if you want to swap positions just let me know."
"Okay," Quinn smirked at me before asking, "are you comfortable with your sister on your lap?"
"I'm handling it okay," I said.
Then she resumed riding me. Grinding her ass on me. Fucking herself.
I began bucking my ass up to meet her downward bounces and reached around and began rubbing her swollen clit, which made her gasp, "Ohhh, God, shit."
Mom said, "Pull over, Austin," which made me stop.
"No, no, keep going," she demanded with a tone that said don't you dare stop. I wasn't sure if it was aimed at me or Dad, but Dad didn't pull over, although he did slow down as I kept fucking her.
"We need to stop," Mom repeated. "They are obviously not comfortable."
"Keep driving," Quinn repeated. "I'm so close."
"What? Close to where?" Mom asked, as she moved a box to look back at us.
"She means we're so close, let's just get there." I covered for her, as she stopped just in time to not get caught riding me.
"Oh, okay." Mom said, looking at us with a perplexed look. My heart started beating.
To my surprise, Mom moved the box back to hide us and Quinn resumed riding me. I became confused. I wondered if Mom knew. Quinn didn't seem to care. I no longer cared either as I was close to eruption. Quinn covered her mouth and I watched her come... and then felt it... as she collapsed on my deck, her juice leaking onto me.
I hadn't come yet.
But I didn't care.
I wanted her to enjoy the game.
Then she surprised me again after a couple of minutes of recovery.
She got off my dick, moved to the side and took my dick in her hand.
She began stroking me and moving around, so her back was against Dad's seat. She leaned her head down trying to suck me, but couldn't reach in the confined space.
Realizing what she wanted to do and realizing that it was definitely what I wanted her to do, I moved up so I was on my knees, my head having to crane awkwardly against the roof as I was too tall. It was enough though for her to be able to take my dick in her mouth.
All these things happening while our parents are inside the car. I thought my dad would have noticed but he kept driving. I wondered what will happen if he found out. My mom, I don't know her mind. It seems she saw us but, why did she covered us.
She bobbed furiously, tasting herself on my dick, which only made the surreal session even more so.
I wasn't going to last long, her mouth was like heaven. And in under a minute... I shot my load in her mouth.
Unfortunately, I couldn't warn her and thus she wasn't ready for the excessive load I shot into her mouth. She gagged and my second rope hit her dead in the face just as Mom moved the box again and witnessed my third rope splatter her daughter.
Mom didn't say a word... just watched in shock... as one last rope shot out of me and onto my cute step-sister.
I looked at my step-Mom, who was staring down at her step-son's dick and her daughter's cum coated face with a look that was completely unexplainable.
It wasn't anger as one would expect.
It wasn't even completely shock.
Quinn had no idea Mom was watching as she
leaned forward and took my dick back in her mouth.
Mom finally looked up at me.
I didn't know what to do.
So I shrugged.
Dad asked, "Everything okay back there?"
"Never better," I said, still with no idea what Mom was thinking.
Quinn took my dick out of her mouth as she added, oblivious that Mom was watching, "I'm persevering."
She leaned forward and licked my dick one more time, before I slid back down and watched as she scooped the cum off her face and put it into her mouth, smiling at me the entire time.
She then began to move back onto my lap, putting my still hard dick back in her pussy, just as Mom moved the box back in position after glancing down at my dick one last time.
My head was spinning.
Both of them.
Mom didn't freak out.
Mom definitely looked down at my dick before moving the box back.
I shook my head at how this surreal, amazing day just got even stranger.
The next twenty minutes, we didn't say a word. I was expecting her to shout at me and alert my dad. Just enjoyed the afterglow of an amazing intimate moment between step-siblings.
Dad announced, "We're here."
I leaned forward and whispered, "That was amazing."
She nodded, as she leaned back into me and ground her pussy on my dick one last time.
Once stopped, she quickly opened the door and got off of me before Dad could see.
I quickly put my dick away, but noticed a pretty large wet stain on my crotch area. That was going to be impossible to hide.
I got out, and Dad said to the two of us, "So you survived."
Quinn, shocking me one more time, replied, "Yes, it was quite the ride."
Feeling my face go red this time, I quickly went around to the other side to grab a box that would hide the evidence.
Mom was out of the car too by the time I went to the other side to grab one of the boxes from the backseat.
She asked, her tone dripping with innuendo, "Did you enjoy the ride too?"
I had no idea what to say.