When there is chemistry between 2 people, I think the flirting just flows. Flirting behavior? I think being attracted to someone, the flirting comes naturally.
So I think it all goes together and it is exciting and fun when you are mutually attracted to someone.
Some people are natural flirts, which can be fun too, I like to flirt, always have but it's the most exciting when you are drawn to someone and there's a mutual attraction there.