When and where does quality coaching work best in practice?

This question was asked during a live session of episode 10 of The Testing Planet: Exploring Quality Coaching, hosted by @fullsnacktester , with @aj_wilson (representing Aviva), and @clare_catherine & @shweta_jaju (representing Co-Op).

We would like to hear what you do at your own companies too:

When and where does quality coaching work best in practice?