Well, if you are standing with her at the bar and you project man to woman scenario around no one will enter your set and try to take her away.. well, most guys won't lets say. On the other hand, if you are not projecting that and people sense you are just friends or the girl is not giving you attention and looking around, then many guys might try to enter your set and game your girl. So basically try to avoid it from happening from the beginning. In case guys do come in between, just ignore them and continue talking to your girl. If they insist on staying, change your body position to be closer to them and engage them in quick conversation.. Ask him for his name, bla bla, then tell him you have to get back to your friends and turn around. Now, he is just blown out and you are back with your girl. Extra credit if you are holding her hand while dealing with him so that no other guy will find the opportunity and jump in while dealing with the first guy.
PS: Most important is not to look annoyed..
Ignore him as if he is not there.. He'll lose his temper and blow himself out.
Don't lie and say she is your girlfriend in front of her.. That's pathetic.. unless she is not looking

Ohh how can i forget.. if she engages him in a conversation and starts flirting in front of you(that's a congruence test).. tell her " Hey, if you’re gonna try to make me jealous by flirting in front of me, at least put on a good show. I haven’t seen bad flirting like that since your Mom tried to pick me up" taken from rooshv.. Or something funny like that.. Never show you are annoyed! You are done if you do
