Place it as the reply after a surprising statement, then follow it with a shocked reaction to close the beat. For a back-and-forth exchange, put it after a greeting-style question and let a laugh finish the sequence, keeping Fr as the middle beat that confirms the joke.
關於此聲音
FrSound is a short prank clip lasting about 4.4 seconds, centred on the brief slang interjection Fr. It is quick and to the point, so it works as an instant reaction rather than a longer bit. The feeling is dry and knowing, like catching a friend in an obvious truth and answering with just that one word.