How does Julia put up a false pretence?

JUlia leads a double life. On the surface she seems the consummate Party member. She waves the flags and banners. She part of the "anti-sex" league and even mentors younger girls. This is simply her cover. Underneath Julia thinks that she is tricking the party. She has, she claims, numerous sexual escapades and a rebellious nature that (she thinks) the Party does not know about.