Hell yes.

"And what would that..." began Jaime, only to have his sister swiftly unlace his breaches and engulf his cock in her mouth. "Oh... ohh, Cersei... You... ohhh..." he groaned as the Queen's head bobbed up and down on his member. Eddard felt a growing arousal that only became more acute when Cersei's hand darted to his crotch and freed his own straining dick from its cloth prison.

Cersei pulled her head off Jaime's dick with a pop, and smiled at her lovers. "This," she said thickly. "For a start." She turned and swallowed Eddard's cock, her tongue laving it, even as she began to jerk her brother off now. Jaime groaned and tore at the Queen's thin garment, revealing the lush curves of her breasts to his eyes. He gripped one pendulous tit in his hand, and Eddard followed his example and grabbed the other. She pulled off of Ned's cock for a moment. "Are you starting to understand me?" she asked with a saucy grin.