Sidewalks in California are generally a crooked mess due to earthquakes, thus, this is a way of describing a person's very crooked teeth.
Christa: "Do you see that guy over there? He's kind of hot..."
Ally: "No! I saw him smile at the bartender while you were showing your tits to that guy in the bathroom...California Sidewalk, dude."
Christa: "Fuck me, right?!"
Ally: "No! I saw him smile at the bartender while you were showing your tits to that guy in the bathroom...California Sidewalk, dude."
Christa: "Fuck me, right?!"
by Ally-sahn February 29, 2012