The location of a lip piercing can symbolize many things:
Top: Usually signifies a promiscuous individual Bottom: An outgoing individual, but still focused and personable
Left: Signifies homosexual individuals
Right: Signifies heterosexual individuals
Guy 1: "Dude, see that girlover there? She has a lip piercing. Her top lip is pierced, I'm gonna go talk to her."
Guy 2: "But its on the left side bro."
Guy 1: "Maaaaann"
Woman: Do you want a lip piercing?
Man: I'm not that into piercings.
Woman: Oh no silly. It's when i literally penetrate you with my vagina!
Man: Count me in!