On top of him?

"I want to ride you," Clara said, stepping out of the pool. She helped the Doctor out of the rest of his clothes and then placed her hands on his chest to push him down onto the wet floor. She straddled him and stared down into his eyes with a little quirky half-smile on her face. Then she raised herself up by one leg and looked down to lift his hard dick with her hand and lower her pussy onto it.

Clara gasped and closed her eyes as she slowly let him slide inside her. When he was in his entire length, she opened her eyes and let out a small gasping laugh. Then she placed her hands on his chest and began to slowly move up and down on his cock. Every few seconds, she would change things up by keeping herself pressed down onto him and just sliding her ass forward and back a little on him before moving up and down again.

The Doctor reached up to cup her soft breasts she she rode him, and after some long minutes of love making, he told her he was going to cum.