Gottschalk advises people to "ask for two lower lip piercings [rather] than snake bites, because there's so many names out there for different things." You want to make sure you're getting what you're envisioning, so feel free to point, describe, or even use images for your piercer's reference.
Anna Beall, a piercer for CowPök in Buffalo, NY adds that piercing terminology is constantly evolving, and it can be hard to keep up. Her advice is to remember that, "A lot of times the internet changes what things can mean, so we just usually say paired lip piercings."