Put it on the punchline beat, right after the setup line lands, so the joke has somewhere to go. Follow it with Vine Boom to underline the reaction, or lead into it with Classic Fart Sound for a double hit before the next line.
About this sound
This is a short, wet fart sound made with a straw, lasting about four seconds, with a sputtering, bubbly burst that rises and falls instead of a single clean blast. It feels crude, silly and deliberately gross, the kind of noise that makes a room laugh before anyone can pretend to stay serious.