Ted puts his arm Joan's shoulders, leaning against her as well, continuing his gentle nattering on. He spots a nightclub with a strange name, which for some reason reminds him of Dirty Dancing, which then leads him to consider Patrick Swayze's career. He can do this sort of association game all day, if she needs.

Although he'll probably tone it down once Sherlock's there. Or maybe actually engage Sherlock in conversation, and she can listen to that if she wants instead.