Place it at the exact punchline beat once the setup line finishes, then follow it immediately with a censor beep over the reaction shot. For a bigger build, drop a dun dun dun moment earlier in the scene so this hit closes the sequence.
About this sound
This is a very short boosted voice clip built around a single spoken slur, pushed loud and distorted for maximum impact. It lands as a jarring shock joke, more startling and taboo than playful, which is why it gets used when a moment is meant to feel suddenly over the line.