Jeff considered asking Jamie's permission, but decided he'd written the rules he wanted. He should live by them.
Keeping the one hand on Jamie's breast, he took the other off her waist and lifted it up to her chin. Cupping her face, he turned her head around to face him. She looked at him with her big blue eyes, from a face still ten years old. Her lips, still bright red with the dew of childhood, quivered as Jeff brought his face on a level with his sister's.
Jeff kissed Jamie on the mouth. She looked surprised at first, but offered no resistance as he used the hand on her breast to turn her body around. Now face to face, he could see her slinky body in her lusty, low-cut dress. He wrapped his arms around her, and pulled him down on top of her.
"Jamie," he whispered. At the sound of her name, she embraced her brother in return.
Jeff slid his hands up her back to caress and stroke her shoulders, then let one hand drift down to cup her butt through her soft cotton dress. His newly grown up sister offered no resistance as his hands explored her body, while his mouth sucked on her earlobes, nibbled her neck, and finally returned to her mouth.
Although she was on top, Jamie was totally passive under her brother's sexual onslaught. He used all his senses to explore the body he'd given her, culminating in using his tongue to part her lips. He wanted to taste her mouth.
And taste it he did. He'd never kissed a girl before, and his sister, with the baby face and the ample body, was everything he'd ever fantasized about.
Well, why shouldn't it be? He'd manufactured that body himself. It may be her flesh, but it was his to explore. And he wasn't done yet, not by a long shot.