What do you mean by throwing the Grail?

The Holy Grail is a way for people to communicate with gods, which is widely used in temples, Taoist temples and folk teachings. The material of the cup is wood or bamboo head, which is cut into two crescent-shaped pieces by craftsmen, and the paired vessels are convex outside and flat inside. The protruding surface of the cup is called "Yin" and the flat surface is called "Yang". If one is Yin, the other is called "Holy Grail".