See an image that represents Tecuilhuitontli in the Visual Lexicon of Aztec Hieroglyphs, ed. Stephanie Wood (Eugene, Ore.: Wired Humanities, 2020-present).
According to the Florentine Codex, this was the seventh month, during which there were feasts and ceremonies, much related to Uixtociuatl [or Huixtocihuatl], considered the elder sister of the rain gods.
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 2 -- The Ceremonies, no. 14, Part III, 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, 1951), 86.
This was a small festival of the lords, the seventh festival of the year. This festival honored Huixtocihuatl, the supposed older sister of the rain gods (tlaloque). Her reed staff was decorated with paper sprinkled with olli. The women who made salt danced to honor the goddess over a period of several days, carrying a cord of flowers (xochimecatl) and a garland of iztauhyatl on their heads. The victims that were called Huixtoti (representatives of the goddess) were dressed like and painted the colors of the goddess. Ceremonial sacrifices were made.
Bernardo Ortiz de Montellano, "Las hierbas de Tláloc," Estudios de cultura náhuatl 14 (1980), 287–314, see p. 291.