Place it as the final beat after the obvious statement, so the reaction closes the scene. Pair it with No No Wait Wait just before the reveal to build the setup, then finish with Oh My God Wow for the closing beat.
About this sound
This short Portuguese voice clip says 'diz pra mim o que eu já sei', or 'tell me what I already know', in a dry, knowing tone over about four seconds. It lands as sarcastic and unimpressed rather than angry, like a calm reply to news that changes nothing. It works best as a knowing shrug in words, turning an obvious statement into a small, funny moment.