wendyshu has already answered this elsewhere, but the problem is in asking poorly, without subtlety, and without gauging the other participant along the way. Rather, provide a slowly escalating ramp that they can willing choose to participate in building up towards the two of you engaging in what you are thinking of as traditional flirtation, or just as easily without social or personal cost choose to never get on in the first place. It also helps to genuinely believe that any interaction you would choose to have with her would be positive for the both of you.