We called it "Roboing" for Robotussin DM back in the day and I've been told that some folks called it "Vortexing", a way to get a trip or a high without failing drug tests and such.
And yeah, wild experience, but not worth the freak out of feeling like you're going to die. Sweat feels really wierd, my skin - my finger tips felt - "leathery" and thick. I think I remember my heart racing, but I don't know if that was from anxiety and panic.