Place it right at the point of impact in a fail edit, after a cartoon slip builds the fall and before a damn meme reaction closes the scene. That sequence keeps the action first, the payoff second, and the group reaction last for viewers.
Sobre este sonido
This is a very short vocal reaction, under a second long, built around a stretched, pained cry of the word pain. It sounds more theatrical than serious, which gives it a funny, cringing feeling, like a tiny mishap being treated as a major injury for comic effect in the moment.