There are three schools of thought when it comes to handling amogs...
1. Blow Him Out
2. Ignore Him
3. Befriend him.
Since my fav is befriending that's what I'll talk about. The idea here to is to get on the guys good side in front of the girl. That way if he's a dick to you he'll blow himself out.
(Guy walks into set I'm in and starts to talk to girl)
Me: "Yo!!!!! That shirt is so cool man! Where did you get it?"
AFC: "Uhhh, Walmart..."
Me: "That's so sweet, you have your own style, I admire that, High five buddy!"
AFC: "Yeah, as I was saying..."
Me: "Awesome man, so what are you out celebrating tonight? You look like the type that could really suck down a few shots and not be phased right?"
AFC: "Yeah..."
Me: (DHV story about driving home a drunk friend)
....
This way not only am I social proofing myself, but I'm DHV'ing and preventing the AFC from gaming my target. Sooner or later the guy will blow himself out by saying something chodey or he'll see he's getting no where and just back off. If all else fails start to buddy angle away from him so he's pushed out of the set while still befriending him, he'll walk away when he sees he's out done.
Personally I LOVE amog battles, no better way to show Leader of Men then to win
Hope that helps, good luck!