Similes Like or As Metaphors

Eric and Richard are like or as a couple of professors talking about using words in a way that is like or as similes and metaphors are used.  How can a conductor use similes and metaphors in the context of a rehearsal setting?  Is it useful?  What are potential issues that can arise if used incorrectly or too much?  Join the guys deep in the mine and go spelunking for ways metaphors can be used in ways that are like or as useful ideas are used.