For as long as humans have had speech, story-tellers have been respected for how their tales and poems taught and/or entertained. Harvard Business School guru John Kotter says, "Those in leadership positions who fail to grasp or use the power of stories risk failure for their companies and for themselves."
There's a time-honored tradition in change work to use stories for healing. A healing metaphor can help clients gain the personal resources and enhanced world model they need to handle their problems. Typically, though, as in the general history of storytelling, the coach decides what story or metaphor will have the greatest effect.
I've used a more client-centered approach, for example with a coach who said she always felt "like the new kid on the block" around her colleagues. I entered her metaphor by saying, "OK, I'm here with you. You've just moved in, and you're the new kid. What's that like? What are the other kids doing? How do they treat you? What are some ways you can get them to include you?" After she answered "They want to play with some of my cool toys!" she realized she had "cool toys" in her current repertoire that helped her feel comfortable with more experienced coaches.
I saw even more possibilities for metaphor work, and attended training in Symbolic Modeling with Gina Campbell. Here, instead of the coach determining the direction, open-ended questions preserve the terminology of clients' metaphors with "clean language," questions that follow the client's lead.
The next time one of your clients offers a metaphor, experiment with being completely spontaneous, playful, nonlinear. Forget about structure, forget about tools from your experience that will "help" or "coach" the person. Simply be present, and see where your client's metaphor leads both of you.