Joyce Carol Oates in the April 2, 2011 show described an interview where two people are paddling together to get somewhere.  We might, I said, be heading toward a whirlpool.  A good interview can be like a dance, with flow and movement and direction.  One wants to avoid the other’s toes.
With either metaphor is the implication of coordinated movement - and no one I think wants to go turtle in our conversation craft.

But what if there is a misstep, some off-footing, and odd locution. How do you find the rhythm again?

I often hear a guest’s rap — it’s been used to answer questions elsewhere, and why not, the answer is good, it drains no real psychic energy to repeat — and try to go in another direction.  Sometimes a guest, knowledgeable in the interviewing arts, will sometimes say in answer to a question, "Well, sometimes people ask me …."  And deftly change course.

So try a question unasked before, or raise an issue that may seem utterly off-topic, but when answered takes the guest by surprise — "I hadn’t thought of that before!" dovetailing with the conscious exposition so cozy and familiar.

That's a moment worth a vin santo you can dip your biscotti in.