Each year a person, a slave (ce tlacatl, tlacotli), would be slain in a sacrifice to this deity, representing him, carrying a green gourd (xoxouhqui xicalli) full of water. They also sometimes sacrificed another slave to this deity at another time of year. The governors of his guild were called calpuleque, and they escorted the person who impersonated the deity, sprinkling people with water, using a branch (huexotica).(central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 1 -- The Gods; No. 14, Part 2, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1950), 21.
The Atlcahualo (ceasing of water, rain), was the name of the first festival of the year. The ceremonies practiced at this time were meant to ensure the rains would come again. They included the sacrifice of small children, preferably children with two cowlicks in their hair, considered like whirlpools, and sometimes called "banderas humanas." The children would be sacrificed atop hills or mountains associated with the tlaloque (Tláloc deities). Other tlaloque are Nappatecuhtli, Opochtli, Tomiyauhtecuhtli (one of the four hundred rabbits that were deities of pulque), and the tepictoton, small legless figures.
Bernardo Ortiz de Montellano, "Las hierbas de Tláloc," Estudios de cultura náhuatl 14 (1980), 287–314, see p. 290.