Tell her to suck him some more?

"Not yet," the Doctor told her. "I want to feel that hot little mouth of yours on my cock some more."

"Oh," Clara smirked. "You're a nasty one aren't you? You want to feel my mouth some more?" she took his cock into her mouth and bobbed on it a few times before taking it off. "Like that?"

"Oh yes," he said. "You're good at that."

"That's what all the boys say," she smiled and took him into her mouth again, working his length with her lips, tongue and hand. Bobbing and stroking and licking and teasing until he exploded into her mouth with a yell, his body shaking.

Clara swallowed down all of his cum and then pulled off and looked up at him, still stroking his hard rod with her hand.

"Mmmmm," she said. "Now... do you want my pussy or my ass?"