Bob,
I just had the procedure you are talking about. I had envisioned it to be something like a stomach endoscopy. Not even close! I can put your mind at ease about this one: no pain OR discomfort at all. No gauze, tape, sprays or instruments of any kind, just a tiny tube housing an even smaller camera and light source. It was lubricated with gel and slid up my nose, past my vocal cords, and down my throat without me even feeling it. REALLY!
This coming from someone who panics and passes out when having blood drawn, you don't have to get stressed out over this one