Learning to exist in different social situations is the mark of an adult. Being willing to do so is the mark of a successful adult.
In the situation you describe, your discomfort was probably vividly evident to your dinner companion, anyway. You didn't need to hide it. In fact, just the opposite.
I don't know...it comes up in annual reviews sometimes that I'm personable and good with other employees and customers, and our sales reps sometimes receive customer compliments on the professional technical assistance I offer.
I don't like having to do tech support for field installations, don't care much for having to meet lots of new vendors and customers and field techs, and someone calling me "personable" feels really strange. My natural tendency is more towards the reclusive side of the spectrum.
Hell, I got high marks in a public speaking course during college, even with some remarks at my good composure, vocal tone, and pacing. I was very nervous and shaking a bit, but I guess I kept my shit together enough to push through and put on a good show.
You could have straightforwardly confessed to him that there were some points of dining there you were unsure about. This would have marked you as a honest man, secure in who you are, who felt no shame in not knowing a few details. It would have shown him that you trusted him personally to guide you in whatever you didn't know.
I may have mentioned something to that effect at some point, perhaps a preemptive apology in case I used the wrong spoon for something.
I get along well with the sales rep who was on that trip, and I did simply ask him privately afterward how things went at the dinner. He said it seemed like I'd done that sort of thing before, and he's the sort who would have no problem pointing out anything like that, rather than try to dance around an uncomfortable answer. But he's not at that kind of restaurant very often either. In the industry I'm in, there are plenty of field techs, customers, and distributors that are regulars at fine establishments like Pizza Hut or Five Guys. This one was a rarity.
So I guess I can put on a decent act around others that is able to reasonably mimic a normal, well-adjusted person. (Unless there's meat that needs to be cut properly.)
It's mentally draining to wear that face so often, but I've also learned that "just be yourself" is complete bullshit for some personalities, and isn't worth the other difficulties it causes.
Meeting such situations head on shrinks them down to the unimportant triviality that they are. And, in case you haven't noticed, people love to impart their knowledge to someone who asks in such situations. Don't you feel the same when someone comes to you and asks for your guidance about something you know and they don't?
Depends how much time I have, and how many times they've asked me the same question before.
Plenty of guidance has been "imparted" in this thread, that's for sure.