Hey!
It's all about keeping the other person engaged as well, if there is a guy there with you then ask him to help you out.
If the friends something "bitchy" do not match that ok, no matter what she says she can't get you angry. You can set a frame like " isn't your friend nice" this is just an example.
Here you have a video, at the end I talk about cockblocks. This weekend I'm going to upload an entire video about how to handle groups and cockblocks
http://www.youtube.com/watch?v=Su7ok6dJ ... 3ol_I_0AKp