Place it right after the crunch is shown on screen, then cut to the eater's reaction for the payoff. Follow it with the Bruh sound for a second reaction, or with the Emotional Damage sound when the teasing needs a bigger finish.
About this sound
This is a short Russian voice clip lasting about seven seconds, in which a man angrily demands to know who is crunching nearby, using a blunt swear word for emphasis. The delivery is loud, irritated and confrontational, which makes it feel both annoyed and funny at once. It works as an over-the-top reaction to noisy eating, turning a small irritation into a dramatic call-out.