There are always going to be suckers trying to be super "cute" when you're gaming chicks, especially at places where there's alcohol involved.
If someone came up to me and a girl I'm gaming like that, I'd simply look at him up and down without saying a word, and then keep talking to the girl I'm with as if no one important was there. Note that by doing so you could get yourself in a fight, but sometimes you have to take your chances.
Another version of this would be to look at him straight in the eye and smile. Big smile with no teeth and without saying a word. Then keep talking to your girl normally and ignoring him. If he tries anything else, smile again while making eye contact. At this point you can ask him something like:
"Let me ask you a simple question, do you think that with the kind of behavior you are showing she will actually be interested in talking to you?..Oh wait, let's try something. (turn to the girl and ask her) Do you want to talk to him?"
Most likely she'll say "NO". If that's her answer, take her by the hand and walk away with her.
If she says "Yes", then she's a dumbass and you're better off without her.
Again, whenever someone comes this rude, there's always the possibility of things to escalate.
Hope it helps and good luck

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