Place it immediately after the messy reveal, as the group's response to what has just been shown, then follow it with Nelson Ha Ha once the laughter starts, so the reaction stays the punchline and the laugh is the release.
关于此声音
A group of kids calls out 'eww' at once, stretching the word into a noisy, overlapping cry that lasts just over two seconds. It feels silly, bright and instantly familiar, as if a whole classroom has spotted something slimy, smelly or strange and answered together. The recording was released through a stock sound library as a plain take of children reacting with disgust.