Mary tried to keep her mind off her new genitals as much as possible. But the longer she sat in her car, the more her pussy and penis ached with need. Her leg moved as her foot switched pedals, and made her inner thigh shift her cock in uncomfortable ways. So she's slip a hand down to reposition it, but at her touch, her cock would grow hard.
"Dammit, how do guys deal with this?" Mary thought, as she continued her struggle to stay soft. Her massive balls underneath made things only that much harder (pun intended). The rested on top of her thighs, forcing her cock up. There was an obvious bulge in her pants, and it was only getting more noticeable with every passing second.
Mary reached a stop light, and breathed a sigh of relief. She looked down, and took the opportunity to adjust her cock again. But her hands unknowingly brushed again a vein. A very, VERY sensitive vein. She almost came right there and then. A car honked behind her, telling her the light was green.
Mary nearly floored it, and raced ahead. But her mind was being consumed by her erection. She didn't care about meeting her friends anymore. She needed to do something about her cock. More than just masturbating, because that wasn't enough. She wanted someone, something to fuck. She needed someone or something to fuck.
Her asshole expelled heat and she felt her pussy pressing against her pants. A puddle formed underneath her as her arousal grew. Her mare cunt was engorged and slick. She needed a release. She never believed in blue balls before, but now that she had them, she understood why guys were so desperate to do something about them.
Mary sniffed the air, and caught the scent of something musty. Something animal-like, and dirty. She allowed herself to be drawn to it, breaking several driving laws as she did. She sped through red lights, and drove on the wrong side of the road a few times.
But she found her destination. Her nose had caught the scent of a farm. Full of all kinds of animals to rut. Mary leapt from her car, and ran to the first creature she saw.