-tzontecon.

pa nosonteco = ipan tzonteco = en mi cabeza = on (or in) my head [Fernando Horcasitas found this form was used in the language of dances that were recorded in various pueblos by ethnographers.] (twentieth century)
Fernando Horcasitas, "La Danza de los Tecuanes," Estudios de Cultura Náhuatl 14 (1980), 239–286, see especially p. 256.ca ana, yn jntzontecon mamalti, in oaoanti, ic mjtotiuj: mjtoa, monzontecomaitotia = All severally took with them the head of a captive, a sacrificial victim, and therewith danced. This was called “the dance with severed heads.” (16th century, Mexico City)
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), 53.

centetl coyotl ytzontecon = la cabeza de un coyote [dado a los nietos en un testamento] (Tlaxcala, 1581)
Catálogo de documentos escritos en náhuatl, siglo XVI, vol. I (Tlaxcala: Gobierno del Estado de Tlaxcala y el Archivo Histórico del Estado de Tlaxcala, 2013), 275.