What causes an ice cream headache?

Actually, the CNS response to pain is a continuum, not an absolute. Central Pain Syndrome is one extreme, but there exist people at the other extreme–people who feel no pain despite large damage to their bodies. We think of the extremes as “malfunction.” But really, even the middle is a continuum. Some people experience more pain with a given stimulus than others. It’s actually pretty nearly a “normal distribution” where the vast majority fall within 2 standard deviations of the mean.

And yes, I DO continue to eat ice cream even though I have experienced pain as a result of eating it too fast. (As I said, I feel the pain in my chest, not my head.) I even have pain from drinking iced tea too fast, but I still drink iced tea. I do so slowly enough to avoid the pain, at least mostly.

As I said, there is nothing about “common sense” that makes a good measure of truth. You STILL have not said what is the obvious danger in holding something cold in your mouth while breathing through your nose. It hurts, yes, but what “danger” are you saying is associated with it?

It IS major suckage, BTW, but life is what it is. You take it as it comes, and try to make it as good as you can.