I am not a rock climber, and had never heard the term "on belay" so I will just share Kathryn's words from pp. 115-116 in the book:
When I was in college, I enjoyed rock climbing in the mountains of Western North Carolina. Occasionally, there would come a time, especially when I was climbing somewhere for the first time, when I'd come off the rock and hang on the rope by the seat of the harness.
Hanging in mid-air 100 feet off the ground surrounded by rock, may or may not sound like something you'd like to do. But it often had some real advantages. Getting off the rock for a minute usually provided some much-needed perspective. It was a chance to see beyond what was just right in front of my face and figure out how to get where I wanted to go. Maybe from there I could see a better route than the one I was trying. Maybe I'd realize I needed to change my form to save energy and climb more efficiently. Maybe I just needed to relax and get my head back in the game.
Whatever the benefit, the only thing that made it possible for me to do any of these things, was the person who was "on belay," anchored firmly and holding on to the other end of the rope. Having a solid belay meant it was safe for me to hang 100 feet above the ground and explore the options for getting from wherever I was to wherever I wanted to be.
When exploring options in the coaching relationship, the coach is literally "on belay," creating a safe space for the PBC (person being coached) to gain perspective, consider the possibilities and deepen the learning. Like all aspects of the coaching conversation, exploring options happens best when the options are generated primarily by the PBC, while the coach listens well, asks powerful questions and guides the process. The PBC is the one who will have to make the "climb" and is, therefore, in the best position for determining the route. The coach is an essential partner in the process.
I thought that was a very good illustration of the kind of coaching I do (or would like to do). On belay... You learn something new every day.