Wow, it would never occur to me that a client would think I was fishing for that sort of feedback. That is definitely reserved for personal private encounters, I would believe. I have had clients say it to me themselves, and well, to be honest, it feels uncomfortable, so I would never go looking for someone to say it. But that's just me.
Like Annessa suggested, maybe when there's a bit of a lag in the conversation, some of us might say, "say something", or "what's on your mind" or if you had a little smirk "what"?
I don't like to hog the conversation, but on the other hand, some guys are not big talkers, so sometimes it can be awkward with coming up with something to say next.
I think you're ready way too much into this, but I may be wrong.