Place it at the end of a burp and fart gag, after the setup and before the group's reaction. Follow it with Eww Brother Eww for disgust, then Nelson's Ha-Ha! for mocking laughter, so the joke gets a payoff instead of ending there.
About this sound
This 15-second clip puts a burp, a fart and a surprised ooh together as one gross-out gag. The burp comes first, then the fart, then the ooh, as if someone reacted to their own noises. It feels silly, crude and awkward, the kind of sound that makes a room laugh before anyone can pretend it did not happen.