An increasingly smaller car

Getting more aroused as she sat in this car with her brother, she felt her dick stirring, as she was practically sitting on it she relaxed that it should stay put. Josh was in his own head, stricken between feeling of jealousy, excitement, fear and lust. He was going slower than usual and taking the long way home, trying to gather his thoughts and think of what to do before he got home to Liz’s ‘workout’. As much as seeing her work out excited him, his anxiety overcame his desire to rush home and get out of a car trapped with his sexy sister. The body next to him was so hard to resist. Glancing over at his sister’s tits, he heard his zipper creak, then he heard the ‘tik’ of it coming slightly undone after he noticed his sisters enlarging fat nipples begin to tent her shirt further and further away, exposing more and more of her dark areola. The increasing pressure of his member was forcing the zipper down slowly with an occasional faint click. Josh was scared, but not unwilling to see what would happen.

Liz was breathing harder, staring at the bulge in Josh’s pants enlarge, neither of them noticing each other noticing each other. The sound of fabric stretching sounded as her nipples stretched further than ever at the sight of Josh’s zipper moving down. Her anticipation and excitement was overwhelming her as she wished and attempted to will that zipper all the way down, and open. Being young and impatient, she slowly reached over and took a hold of Josh’s zipper startling her brother. Josh, his hands glued to the wheel, couldn’t speak, and couldn’t bring himself to stop his sister as she slowly pulled it down. Her heart raced as the shape of his cock head thrust through the opening, pressing against his boxer shorts, a large wet spot at the tip forming as she brought her hand closer to touch it. Josh was attempting to make resistant grunts in protest, but all he could manage was a squeak as her hand fell around his cock through his underwear. Liz sharply inhaled as finally held it in her hand, feeling it pulse, and then began to unbutton his fly.

Josh’s dick surged forward from its confinements in relief from his boxers. “*gasp* Liz!” Josh was finally able to weakly murmur, without attempting to stop her, but slowing the car to the lowest legal speed.

“Oh c’mon” Liz breathily said, her eyes wide and her own dick stirring, “I just wanted to see what you were hiding… little brother.” This caused Josh’s already large penis surging slightly larger at the words. Liz saw this and processed it for a second, quickly realizing that it was a response to being outgrown. She was intrigued, watching the penis strain further from the cloth flaps of the underwear. Her penis couldn’t take it anymore, and with a loud gasp, Liz’s panties broke and shifting her body her dick flung out before her, hitting the bottom of the glove box slightly before sliding past and slapping against her stomach, allowing her balls to fall and hang over the seat. Sighing in relief she smiled at her brother who just pulled over to watch the event. Hypnotized, he watched Liz’s cock, already bigger than his, lengthen up her abs to finally rest its head, as thick as his wrist, just within the bottom of her cleavage. She then reached over and ran her finger down his dick which strained to its biggest ever 10 inches. She began to breath louder, her nipples forcing themselves out of her shirt, pressing into the dashboard. Josh gave a little squirt, but stayed hard as ever after finally seeing those thick chest sausages.

“Do you think I’m too big Josh?” The very large college student asked. Josh, swallowing hard, slowly shook his head no, entranced by his sister slowly stroking one of her nipples. “I can’t imagine how it must feel to see your little sister, your tiny younger sister, gradually grow bigger… and bigger… and bigger! To see your weak helpless little Liz outgrow her big strong big brother” She may have only been indulging herself right now, but what she was saying was having a profound effect on her brother. “Going from having to look allll the way down to see her, to now having to up at your little sister. You don’t mind that do you? Or rather, you won’t mind looking waaay up just to talk to me would you?” Josh was paralyzed with arousal.

“…I guess… not” Josh said.

“Oh good” Liz said excited in a haze of lust, “that means I can get even bigger!” Josh choked, and his hips tensed, as more precum started to flow out. Liz, suprising herself, following her instinct leaned over and took his cock in her mouth. Josh gave a shivered “oh god” as there was nothing he could do now, and shot his load into her mouth. Liz, only slightly surprised, sucked on his dick and swallowed all he gave, giving an approving moan while doing it. “Mmmm, that was good Josh,” she said, still breathing hard, slowly bucking her own hips.

“My turn” she said now leaning over her lap, causing her dick to fill her cleavage. Being so over excited she began immediately bucking her hips quickly, shoving her tits together around her huge cock, moving them up and down as she bucked faster, “Oh Josh! I’m- I-I’m gonna…- NNNNGH!!” Liz’s body began to quake, Josh pushed himself back against the side of the car as her rumbling became so heavy that it was rattling and shaking the car, the windows completely fogged from both their resperation. Liz grabbed her dick and pushed it forward against the dash screaming. And it began. Her dick started to grow in her hands, and in mere seconds it was 3 inches longer. Then her body’s rumbling peaked, shaking, as her cock blasted cum all over the roof. Liz started to hunch over, and Josh noticed her shoulder and back muscles inflating. A full 30 seconds pass before she stops cumming- but she just keeps growing. “I-It’s never lasted this long b-before“ Liz managed to mutter to her brother with a strained look on her face, as her breasts completely filled the space between her legs and her chest; pressed against the dashboard with her fat nipples just peaking over the top, they began to lengthen too, sliding along the top surface of the dashboard stretching towards the windshield. Josh was getting frightened for his sister, and pressed on the gas to rush home.