Sex, she wants sex. In my experience usually big talkers are small performers. So next time she says she will "eat you alive" tell her to prove it.
Asking her to prove it seems fine, but assuming she wants sex, is not something you can afford in 2023. Maybe this girl is op's boss or some other work thing? Tread carefully. Feel the waters, not the butt.
"Would eat [person] alive" = sex. More specifically the type of sex that satisfies a primal instinct, just like a hunger; "I got this urge, this craving, and I need to satisfy it, and you look delicious". What she's saying is that she'd fuck you dry. This sounds genuine for me, based on your account, but keep in mind that there's a chance that she's just joking around.
You are not flirting. Specially since you're behaving towards her the same way as you'd behave towards others ("I don't really take shit from people").
The big main question here is: do you want sex with her?
If you want sex, you need to discover if that's what she wants too; then some flirting could be good here. Someone said to tell her "prove it", I think that it's a great way to lead it this way; and if she's just joking she'll likely back down, without too much harm.
If you don't want sex, and you feel uncomfortable with her behaviour, a simple "this is unfunny, could you stop it?" might work, without making her lose too much face. If you don't want sex, and you don't feel uncomfortable with her behaviour, just... keep doing it as usual?
REMINDER: those things are heavily culture-dependent, so take any advice from the internet with a grain of salt. Including mine.
She sounds a bit immature and that's a red flag IMO. If you are here asking what she wants, to me it means that you are not that much into her. If you wanted to bang her you wouldn't be asking about it here, you would know already...
...which brings me to the point: you can only flirt on purpose. Everyone is different and flirts in a different way, what is flirting for some is just their default way of treating people for others. As long as you are not leading her on purpose, you are in the clear. But if she's accusing you of flirting, which would be another red flag imo, I would suggest just stop being friendly with her. She sounds like problems you don't need.
Flirting looks different to different people. Likely, she is either into you or feels safe enough to be flirty with you in a manner that she doesn't with others, potentially without intent of going further.
Saying that she would eat you alive is her saying that she is confident in her sexual prowess and appetite (or wants to project such). If you're not available or interested, could get awkward. If you are, probably just roll with it.
Just to be clear, how old is this woman? And how exactly do you know her?
Something seems a little off, but I can’t put my finger on it