They should fuck.

The Doctor allowed himself (or so he would later like to think; in reality he didn't have much say in the matter), to give in fully to his urges. He pulled Clara up so she was standing in the tub. He was vaguely aware of the sudsy water dripping off her gorgeous, glistening body. He turned her around and ran his hands over her wet, curvy bottom. His fingers found her wet sex and he touched her there as she moaned and ground back into him.

He guided his hard cock up to her from behind and slapped it on her ass cheeks a few times; right then left then right then left. Clara moaned with excitement and impatience. Finally he slid his hard rod into her pussy and she gasped as he pressed himself into her fully. Hands on Clara's hips, the Doctor began to fuck her from behind.

"Fuck me, Vance," she gasped, breathlessly.

The Doctor's pants got soaked as he slammed into her wet bottom, his cock just sticking out from his fly. Clara's pussy was so tight and hot that after just a few minutes, the Doctor knew he could cum at any moment. It was only a matter of sheer willpower that kept him from exploding inside her.