Place it right after the offer is shown, before any reply, so the villager becomes the reaction to the deal. Follow it with Hell Naw Dog when the trade is refused, or leave it as the only reaction in the scene.
About this sound
This eight-second clip is a run of wordless Minecraft villager hums and mutters, the nasal noises the game's traders make instead of talking. It feels awkward and deadpan, like a silent shrug from a shopkeeper who thinks your offer is terrible. It comes from Minecraft, where villagers communicate with those noises rather than spoken words.