to make the sound as when shaking a vessel of water; or, to make the sound of a rotten egg when shaken (?) (see Molina) (seemingly an onomatopoetic word)
IPAspelling:
kokoʃoːni
Alonso de Molina:
cocoxoni. lo mesmo es que cocoxoca. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 24r. col. 1. Thanks to Joe Campbell for providing the transcription.