I think it's more speculative to lead to more theoretical discussion and sort out some practical applications of what you thought. I know for instance I do this all the time with my INTJ dad, in fact on a daily basis.
Today I was busy sort of boarding my windows with plastic thermal insulation and I figured my dad being an engineer could solidify some of my theoretical assumptions. So I asked a somewhat naive question about "how you would go about doing this task in a more professional manner, how does wind and heat circulation effect your processes and procedures, and how is that calculated and accounted for in a engineering manner." That was the question I wanted answered...
But if I were to outright ask it I would not allow his expertise to shine through, furthermore since I'm obviously not an engineer some of my assumptions would no doubt be misguided. I've seen many shows on just how insulation is important and could recite and ask more pointed questions based on my knowledge, but in that situation a little naivete and obliviousness in my mind served me much better. From then on I could proceed to really solidifying my knowledge with more accurate information because I let him articulate his thoughts and perspective without interference that would have no doubt resulted from a more blunt approach.
In general most people are not professionals who like to be called "off duty" to discuss more intensive and demanding topics so it's always best to segue-way into them. It's amazing how well that approach can serve you. Sometimes it also helps to strip premises that weren't really analyzed or thought about as well. I do this constantly with my ESFJ mom and it helps me increase both my verbal ability and helps to get her to talk about the things I want without being confrontational and brief.