Eating the marrow to know the flavor:When you eat the marrow once, you know how delicious it is. Originally, it meant that the marrow tasted so good that it was so delicious to eat that you wanted to try it again afterward. Later, it was generalized to mean that after experiencing it once, one would like to try it again. It is a metaphor for a person who gets benefits once and then becomes insatiable. This word is derogatory. It is often used to describe a thief, a burglar or a woman who steals from a man, meaning that if you are not caught once, you will want to do it again. It can also be interpreted as a desire for dissatisfaction or in order to satisfy a moment of greed and freshness, but after doing so, feel stimulated and satisfied, and later want to continue to do, may evolve into a habit or even a hobby.