I'm beginning to get the hang of how to handle shit tests, but I was caught completely off guard last night.

One of the girls who tagged along last night to the bars would not stop throwing shit tests my way. At first, it was nothing I couldn't handle through simple agree and amplify or just ignoring her. Even when she pulled some bullshit like giving me a titty twister after some banter/insults, I threw it right back and slapped her tits. However, as the night went on, her shit tests became more and more cutting and profanity-laced, to the point where they could be called insults. I don't know if she was drunk or just being a bitch, but almost every other word out of her, even when talking to her friends, was cunt, bitch, fuck, shit, etc.

My question is this, how do I handle women like that? At what point does it go from banter to straight-up insults? If she does throw insults my way, what is the right way to handle them? I can't exactly ruin her night with cutting insults, since she is a friend of a friend, and I would look like a butthurt beta.