Note: Everyone in this story is 18 years old and above. This story contains some incest between brother and sister, so if it makes you uncomfortable then please find another story. Most importantly, this is a work of complete fiction.
*
Mark could only think about Lisa as he drove out of their gated community. She was the only person on his mind as he struggled to control the accelerator because of how his legs were trembling. Even the hand holding the steering wheel was slightly trembling; he could feel his arm tremble, but upon glancing at his arm, he could not see it actually tremble. Not yet, anyway. His right hand on Lisa's thigh was still; there was no feeling that it was trembling.
In fact, as he continued driving, Mark moved his right hand upwards, the fingers pressing down against the denim fabric covering as it made its way down to her inner thigh at the same time. He heard Lisa give off a sigh before she parted her legs slightly, allowing his hand to reach down to the warm feeling between her legs. Upon reaching that warm valley, Mark pressed down into the denim covering her pussy lips. He heard Lisa go "Ummmmmmmmm!!!" and the passenger seat creak slightly as his fingers pressed down and caressed her covered pussy.
"Oh, Mark," Lisa whispered with her eyes closed and her head resting against the head rest. "That feels good." Coming to a stop at the traffic light, Mark pressed harder as he quickened his 'come hither' motions, using his fingers to press harder into the fabric just beneath her zipper. Even though his fingers weren't penetrating her pussy lips, Mark could tell Lisa was enjoying it from the moans escaping her lips as well as her visibly trembling body. Even as cars came to stop on either side of his car, Mark's fingers continued their motions. Lisa was moaning. "Yes, Mark, fuck... you are making me feel soooo good." Licking his lips, Mark changed the motions made by his fingers--he was now drawing circles as he continued to press down.
"Haaaaaaaaa," Lisa breathed out while her eyes, which were already closed, tightened shut as she slightly arched her back before taking in a deep breath. Mark glanced at his sister, who was panting hard as she adjusted herself on her seat while opening her eyes slowly towards him. He then glanced to her left and saw the driver--a middle-aged woman with red hair tied into a ponytail and wearing a suit--looking at him with a questioning expression. He smiled at the stranger before his eyes refocused on Lisa, whose eyes were once again closed, her head facing his direction.
"You are so beautiful," Mark said. Lisa opened her eyes and gave him a smile that had his heart racing once again. Mark slid his hand away from her covered pussy and brought it back up to her thigh. He noticed the questioning expression on Lisa's face, as if silently asking why he wasn't continuing. Mark said, "Trust me, I would love to continue what I was doing, but..." He glanced at the woman in the other car, who was now staring out her own windscreen, and then refocused his gaze on his sister. "That lady in the other car was watching us."
Lisa chuckled before she turned her head towards the passenger-side window and then stared at the woman who had been looking at them earlier. Lisa turned her head back towards Mark and smiled. "She's no one we know." Mark chuckled at Lisa just as the light turned green. Mark pressed down on the accelerator while thinking that Lisa was right; the woman was a stranger, and it didn't matter if she had caught him 'dry fingering' his sister. Now, Mark wanted to just stop somewhere isolated and then take Lisa in the backseat, where she would be riding his cock to orgasm. He imagined carrying her out of the car and then bending her over the hood of the car and ramming in and out of her like an out-of-control piston.
As he drove, Mark's imagination turned to Lisa screaming in pleasure as he fucked her on the field at the school stadium or on his bed, surrounded by people watching him take his sister. Mark could feel himself sweating as his thoughts raced--more scenarios being created in his mind, the subject of his thoughts being his sister. He could feel and hear himself breathing hard as he continued driving the car.
"Mark?" He returned to reality, his eyes on the traffic light having just turned red.
Mark came to a stop at the traffic light before turning his head towards Lisa, who was staring back at him with a quizzical expression. "You look tired." Mark shook his head before turning his gaze down to the hand on her thigh. He then looked back up at Lisa and said, "Undo your zipper." If he could not have sex with Lisa now, he might as well finger-fuck her properly. He hoped that would get Lisa out of his thoughts temporarily.
"Now?" Lisa chuckled before she looked around at the cars stopping around them. She then looked back in Mark's direction and chuckled. "Mark, they could see us."
"I'll be careful," Mark said as his hand travelled once again to the valley between her legs. "We have a few minutes stuck here, and... well, I want to see if you can stop bringing attention to yourself while we have some fun."
