I don't think "car back" means anything to someone who doesn't keep to the right. Tell her "we all need you to keep to the right, please." Remind her of that as often as necessary. Call her "Lefty" if she has a hard time changing her habits.
My rant is on people who don't say anything about what's bothering them until they've gotten angry. If you want to maintain the paceline and find yourself gapping, say "gapping!" Don't let me drop you then wait until you catch up to yell at me. If it seems it's taking me a while to come alongside and take a pull, don't just weave and shiver a bit, say "pulling off!" wave your arm or something. Don't stew. That's my rant.