The shape of a Pringle is referred to by the people at Kellogg's, and science in general, as a hyperbolic paraboloid. Now, consider how they are packaged. Stacked more than foot high, with each of the Pringle's sides flared upwards, with the tips sloping downwards -- like the Pringle man's moustache. In this state, the concave of the crisp (they're "crisps," not chips) arch just like this. Remember that. This is important.
Now, as my in-office colleagues are still willing to eat random things I give them, for some reason, I asked 10 of them to reach into a Pringles can (the flavor was Loaded Baked Potato, in case you are taking notes) and eat exactly one crisp. Nine of the specimens in this super low-effort survey took a Pringle out of the can, flipped it over, then placed it in their mouth, like this. It fits right on the tongue this way. It's almost primal. It just makes senses -- and it's exactly how I used to do it.