A cormorant is a bird that dives for fish underwater. Some Chinese villagers have reared these birds and trained them to 'fish' for them. Rings are put around their necks so they can't swallow the fish they bring back up to the boat.
But after diving seven times, the cormorants will refuse to dive unless the ring is removed so they can eat a portion of their catch. Coaches are a bit like cormorants. After giving a bunch of advice, they expect to see some of them put into action and some results to follow.