Place it right after the reveal in a short edit, then follow it with Hell Naw Dog for a second reaction, or pair it with Bark and Fart when the joke needs another gross payoff in the same scene.
About this sound
This short clip pairs a stretched-out, exasperated 'what the hell' with a sudden, wet fart noise right after it. The contrast makes it feel disgusted, silly and deliberately gross, like catching something awful at exactly the wrong moment. It works as a quick reaction to bad smells, bad takes and moments that go from confusing to repulsive in seconds.