Michelle gave a throaty laugh as she ran her hand along Marcus' new muscles. "You know, I think I might have a little more fun with you."
Still frozen to the floor by the succubus Marcus shook his head. "No please, I don't want to die."
Michelle licked her lips, seeming to actually consider his pleas for a moment, then nodded. Marcus' brief relief soon gave way to more panic as the succubus gave him a dark smile. "I won't kill you, but we're going to play a little game." She lifted her hand to show him her palm, and dragged one of her claw like nails along it, dark almost blackish blood welling up at the wound. She held her hand over his mouth letting a few drops of her demonic blood enter his waiting mouth.
Marcus coughed and spat, trying to get the blood out of his mouth, but he knew some went down as a painful spasm wracked his body. He felt a heat growing inside him, wild thoughts began to fill his mind. As he looked at the succubus, almost all he could think of was pushing her to the floor and having his way with her.
Michelle laughed, seeing the lustful look in his eyes, "So here's the game. I ramped up your libido, as you probably have noticed, but there's a catch. Every time you orgasm you'll become a little bit more like me.. well, you'll still stay male, so I guess I should say you'll become more and more an incubus. If you aren't fully changed by the night of the full moon, you'll revert back to the way you are now, minus the hyper sex drive, and I'll leave you alone forever. If by then you are changed all the way, you and I are going to have some more fun. So in other words, by midnight in three days if you have about 6 orgasms, you will become an incubus forever."
Michelle leaned over running her tongue along his hard cock. "And well, I'm a demon, so I'm not going to be completely fair." She gave him a wicked grin and took his member into her mouth, deftly working it with her tongue. His already hyper aroused state, and the fact he never had sex, even oral, before drove him to almost instant climax. The succubus swallowed his seed as she watched his body shudder. His large member grew another inch, his balls swelling up even more. His skin darkened slightly, taking on a faint reddish hue, as his brown hair stained black, his eyes becoming slightly yellow.
"5 more to go, I don't think you'll be able to resist." With that Michelle flew out the window, the paralyzation on Marcus dissipating as she left.