Many guys can fall into the trap of talking about themselves too much when a girl says something about them.
Do you really want to do what EVERY other guy does? Do you really want to jump on HER frame like that?
This is what every other guy does:
Girl: You're such a flirt!
Guy: *something related to him being or not being a flirt*
This is an example of something I do:
Girl: You're such a flirt!
Chief: And you're beautiful
I'm always trying to flip the frame so that we're talking about HER. And, really, if a girl tells you that you're a flirt, she just might really be saying "I like you," and that should be rewarded with a compliment! Or, if what she really meant was a shit test, you didn't respond to it if you just said something like "and you're beautiful" so you pass it.