I was looking up how to do a "witness talk." Some might call this "confessional preaching." In surfing the net I came across the Cursillo method. Being a Cursillista, myself, I was surprised at everything that went into it.
It seems that you need four people. One is the speaker giving witness. Another is a friend praying in the chapel, or wherever. Another is called the responder. Finally, you need a priest or someone knowledgeable to add scriptural and doctrinal backup.
I was surprised at the "responder's" role. The responder asks a question, or affirms, or whatever is needed, after the witness Talk. He helps the speaker by sitting in the audience and gauging the reaction. The responder might affirm what was witnessed by affirming what was said, or expand himself by adding something, or even ask a question that he thought might need further explanation.
When you think about it, every speaker should have a "responder".
Oh, and of course, some other friend praying in the chapel.