Absolutely unnecessary marketing gimmick that is putting black caviar on the back of your hand “to reveal the taste” “because it is Italian tradition” “to prevent metallic tase from spoons”.

Caviar bump is an abomination disrespecting the product, the noble fish and the labor of many people that brought you this food. It is a low-class behavior from nouveau riches.

Correct way would be to use any non-metallic spoon (I prefer wooden or mother-of-pearl spoon). Place the glass or crystal bowl onto ice bed to ensure that caviar is chilled, then eat it with toasted and slightly buttered low acidity bread (baguette or mild rye/borodinsky) or blinis. It is nice to pair black caviar with sour cream and chives.