Seventh among the Lords of the Night, Tlazolteotl governs every ninth date beginning from day seven of the tonalpohualli, her turn moving through the full range of day signs and trecenas across the 2340 days required before the nine day and 260 day counts realign. A date under her night carried, in the tonalpouhque's layered reading, an association with the confession rite's own logic, a day read as suited to clearing old transgression or beginning a course that required discipline and eventual reckoning, an interpretation drawn from her known ritual role rather than from any surviving day by day manual specific to the night lords, since Sahagun records the nine as a fixed sequence without a separate divinatory text attached to each.
The confession rite itself was not tied to any particular date in the 260 day count, being available to a penitent essentially once and near the end of a serious transgression's weight on the conscience, so Tlazolteotl's place in the calendar priests' reading of a given day is best understood as one register among several a diviner weighed for a birth or an undertaking rather than as scheduling the confession rite itself. Her position immediately before Tepeyollotl, the jaguar aspect of Tezcatlipoca who follows her as eighth, places two of the sequence's more severe figures adjacent to one another near its close, though the compilers of the codices record no explanation for the ordering beyond the list itself.
Sources Cycles of Time and Meaning in the Mexican Books of FateElizabeth Hill Boone with Florentine Codex: General History of the Things of New SpainBernardino de Sahagun; translated by Arthur J. O. Anderson and Charles E. Dibble