Place it just after the setup shot, as the first reaction to the mishap, then follow with the Darth Vader Nooo for a bigger payoff and the Fail Sound Meme to close the joke.
Über diesen Sound
This is a just-under-four-second robotic scream from R2, the little astromech droid, a rising electronic wail that sounds like WEEOOWWW. It feels panicked and frantic, but also funny, like a tiny machine in over its head. The clip comes from the Star Wars films, where the droid often squeals in alarm during danger.