The aim of this exercise is for one participant to practice the assertiveness technique known as negative inquiry. This technique comes from When I Say No I Feel Guilty, by Manuel J. Smith. Negative inquiry involves listening to criticism, clarifying your understanding of those criticisms, and either using helpful information or ignoring it if it's manipulative.
Example: "Will you knock it off?" A response to this might be, "I'm not sure I understand. What is it about what I'm doing that creates a problem?"