Nikki couldn't resist the pheromones that the donkey man was giving off. Biting her lip, she briefly considered fleeing but the allure of the huge musky cock proved to strong. She began to remove her clothes causing the man to laugh. "Guess you were just a bitch after all, huh?" Once Nikki had finished stripping doubt returned to her mind. "I'm not a bitch! I'm doing this for you." She gestured to his throbbing rod. "You clearly need it buddy." The man just chuckled as Nikki bought into her own weak arguement. She fell down on all fours and stuck her ass out at the man. The mutant, who's name was Keith rubbed his flat dick head against Nikkis soaked cunt. He suddenly pushed forwards and grunted as he hilted his shaft into her snatch. Nikki let out a whorish moan as he began to thrust. "Look at you!" Keith growled, "Nothin, but a bitch!" Nikki still lost in delusion shouted back, "No..I'm..Not!" Keith suddenly ripped his cock from her causing her to let out a frustrated whine. He observed her pert ass sticking out at him and sneered. He pressed his flat cock head against the pucker of her ass causing her to yell, "What the fuck are you doing back the-AAAH!" Nikki let out a squeal as Keith rammed her tight ass. "Admit It!...You love this!" Nikki rocked back against his cock and groaned in pleasure, "Yes..I'm..I'm-I'm you're bitch! With her confession she came spraying his groin with her juices. Keith roared and unleashed his seed into her ass before pulling out. Nikki laid there panting for a time before coming to her senses. In shock of what she'd just done she grabbed up her clothes and ran. Keith shouted after her, "Come back anytime bitch!" Keith chuckled and returned to his work. Nikki hid behind a tree and redressed wincing at her sore ass. She quickly began to hurry home hoping she didn't encounter any more mutants on the way. However she failed to notice the unnatural heat in her groin and the strange sweat on her brow as the virus took root.