The date of lên đồng rituals are typically planned to coincide with a festival, anniversary, or the inauguration of a Mother house, although rituals may also be performed at more informal occasions. Rituals are generally held in temples, shrines or similarly sacred locations. Joss paper—which may range from flowers, cakes and sweets to alcohol, cigarettes and jewelry—and, on certain occasions, even Coca-Cola cansCoca-Cola cans are used particularly for their colour, as noted in Kendall (2003): "The medium pays special attention to the color of the votive offerings, so that each spirit receives offerings that are the same color as the realm with which she or he is associated." (p.261) Red is a colour associated with the "celestial sky palace", therefore the red cans are "appropriate offerings for spirits from the Heavenly Realm". (p. 260–261) —must be purchased. Mediums generally also purchase a number of different costumes to be worn during the ritual. Before the main ritual takes place, mediums undergo several days of purifying rituals, involving abstention from sexual intercourse and eating meat.
