While talking about sex, Oates refers to it as "intercourse" but Garfunkel says she prefers "coitus," which Sheldon frequently refers to sex as on Big Bang Theory which both girls guest starred in.
Oates runs into Daniel and Caroline in a store. Daniel tells Caroline that Oates is an actress and then tells Oates that Caroline is a physics professor at Cal-Tech. Another nod to their time on Big Bang Theory.
When Garfunkel and Oates are in the car talking about sex, Oates notes that she calls it intercourse. Garfunkel then says that she prefers to call it coitus. A clear nod to both of their times on Big Bang Theory where Sheldon Cooper refers to it as coitus as well.