to suck or gnaw on something (see Karttunen and Molina)
IPAspelling:
pipitsoɑː
Alonso de Molina:
pipitzoa. nitla. (pret. onitlapipitzo.) chupar, o roer algo. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 82r. col. 2. Thanks to Joe Campbell for providing the transcription.
Frances Karttunen:
PIPITZOĀ vt to suck or gnaw something / chupar o roer algo (M) T specifically marks the vowel of the reduplicated syllable short. redup. PITZOĀ. Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 197.