to request and procure something with diligence, beg, pray (see Molina); to cup with the hands (see Siméon's interpretation of "cavar" as "ahuecar")
IPAspelling:
mɑːtɑtɑkɑ
Alonso de Molina:
matataca. nitla. (pret. onitlamatatacac.) cavar con la mano, o pedir y procurar algo con mucha diligencia. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 52v. col. 1. Thanks to Joe Campbell for providing the transcription.