Network buzzwords. Flammulina velutipes dipping sauce for four days and four nights means "the limit of patience". Flammulina velutipes are usually the ingredients of hot pot, but many hot pot restaurants will make Flammulina velutipes into vegetable bags and dip them in a bowl with Chili sauce, so netizens use "Flammulina velutipes dipping sauce for four days and four nights" to describe the limit of patience.