Place it at the moment the unread chat appears, then follow it with Olha a Mensagem to repeat the nudge, and finish with Abriu o Áudio once the reply finally arrives.
About this sound
This is a brief Portuguese voice clip, lasting about two and a half seconds, built around a whistled fiu fiu followed by the line telling someone to look at the message. It feels cheeky and lightly urgent, like a playful nudge rather than a scolding. It circulates as a messaging meme audio used over unread-text jokes, with no widely documented film or television source behind it.