Dream of falling

I was at a party or some social event, I was having a good time enjoying a conversation with Natalie, when at some point while we were both silent and someone else said something and Natalie got in a defensive position, folding her arms and pushing herself in the couch. I notice, and turn towards her and pull myself closer and ask her what's wrong, she sighs and turns towards me her legs falling over mine. "The Sign" she said. I not fully understanding, thinking its political, say "I don't know much about the The Sign, can tell me more?" at this point we are very close to each other and she was about to to tell me what The Sign is when we see someone walking to the door, who was Natalie's ride home. "I'll tell you later," she says at the door then leaves. I am still wondering what The Sign is.