No, he wants something more... intimate.

Joffrey pulled back from his mother's mouth, noting a certain disappointed look on her face. He was not going to end this historic occasion by flooding his mother's tonsils with seed like she was one of the cheap whores Littlefinger used to try and get his favor with. No, this required a more... definite shattering of certain boundries, so that his mother understood who was in charge now.

"Stand up," he stated. Cersei did so easily, now proudly showing off the tits she'd earlier try to hide from him, smiling as he stared at them. "Now, get out of that skirt." His mother removed the lower portion of her dress, letting it fall to the ground, smiling as he regarded her nude form. Joffrey gulped, his mouth suddenly dry. "Now... go lie on your bed, and spread your thighs," he whispered.

"Of course, Your Grace," she answered serenely, setting herself on her bed and opening her legs wide. Joffrey stared a moment at her open cunt, moist and ready for him, and then, removing what remained of his clothes, went to join her. Her breasts trembled as he settled over on the bed, and she licked her lips as his cock rubbed at her slit. And then he gave a shove of his hips, and he was in her. Cersei gave a groan as he plunged into her wetness, while he took a deep breath and marvelled at how tight she was.

Then he was all in her. For a moment, they remained like that, staring at each other, and feeling this forbidden joining.