As they say, there are two rules in improv: Never say no, and never ask why. When another actor asks 'Why?' or says no to something you're suggesting, then it's very clear that they're putting the onus on you, because they're not comfortable with it themselves.
“We were once friends with the whites but you nudged us out of the way by your intrigues, and now when we are in council you keep nudging each other.”
“Nothing is more despicable than a professional talker who uses his words as a quack uses his remedies.”