Stop Rose and investigate

Much as he wanted the attention, the Doctor thought he'd like it when Rose wasn't affected by externally produced hormones.

He gently pulled her up, and kissed her.

"Rose," he said, "I love you, and I want to make love to you but not here, not now".

Rose heard the Doctor saying he loved her, and this thought temporarily blocked the hormones from working. In her clear thinking she was ready to explore.