Use it as a single beat inside a reaction sequence, then follow it with Auughhh for a bigger recoil or Hell Naw Dog when the moment needs a clear refusal, keeping it as the opening beat and the second sound as the response.
About this sound
This is a sub-second Japanese vocal groan from Yajuu Senpai, a single strained 'n'ah' cut short before it can finish. It feels abruptly uncomfortable and deliberately absurd, turning a pause into a suggestive interruption. The voice comes from A Midsummer Night's Lewd Dream, a 2001 Japanese production whose clips became part of the long-running Inmu meme culture.