It means she's just doin' a little flirting, nothing too serious. She's testing the waters a little, or else just horsin' around.
What I find more interesting are the answers posted here that include the "disclaimer" that it could be sexual harassment. They have to say that because of the fear that someone will say that if a girl can do it then a guy should be able to as well and every single woman on God's green earth is gonna say that for a guy to do it is sexual harassment, if not sexual assault! Actually they are stuck because if it's OK for a girl to do it, but not for a guy, then they have adopted a double standard. And the one thing politically correct women all agree on it's that there should be no double standards.
So then how come it's OK for women who are "just kidding around", but not for men in any case?
I love seeing people squirm.