When I was going in Jama'at one purana saathi told, that Rasulullah did actually not lick the whole of his five fingers after taking his meal like some do in a quite disgusting manner. He said, 1) Rasullulah ate only with three fingers and 2) He ate not in such a way that the whole fingers let alone whole hands would get dirty. Supposedly he only licked the inward tips of his three finger he ate with.
Is there any basis for this claim? If yes, are there more Sunnahs we laymen misunderstood and practice on in a more inappropriate (disgusting) way?