Verb. From Japanese.
“To take big mouthfuls of food repeatedly”
This is another onomatopoeic/mimetic word from Japanese that has uses both in the gastronomic sense described above, but also in a few other contexts. They mostly revolve around the mouth and lips, but it can also refer to objects that are ‘flapping open and closed.’ You can also have a ‘pakupaku ningyō’ (a puppet with a moving mouth) or one of the origami pakupaku shown in the picture that are occasionally referred to as ‘fortune tellers.’