Place it right after the awkward line in your edit, then follow it with the Kiko Laugh Sound Button so the reaction sells the gag. For a chat-style sequence, put the WhatsApp Message Sound Button before it, as if a normal message caused the reply.
關於此聲音
This clip is a very brief fart sound effect lasting under a second, a single short bodily burst with no voice or music. It feels cheekily gross and instantly rude, turning an ordinary moment into a childish joke the listener gets right away without any setup or explanation needed at all.