Step one: Always have gum on you. Preferably bubble gum to be an extra asshole. But make sure the gum is individually wrapped.
Step two: Wait for the power play. Most beginners will do the idiotic silent treatment. This is to “control the awkwardness” or some bullshit. This is when you pull out the gum and loudly chew it leaving the wrapper somewhere for them to clean up.
Step three: Keep them on topic and acknowledge what they are doing. Often deflection or subject changes are a power play. Don't let it happen and bring it back to your raise, vacation time or whatever. If they do it again point it out. You're trying something you saw on YouTube and it won't work on someone who knows you're doing it.
Step four: Once they start acting human again, spit out the gum. You only need to be rude because they are. You may not get to this step and you'll have to smack and blow bubbles the whole talk. But I've usually gotten what I need using the gum method.
If they are eating and have chips or some sort of finger food on the side. Skip the gum and eat off their plate without asking every time you get a response you don't like.