Place it immediately after the rude remark in your edit, so the reminder answers it directly. Follow it with Law and Order Dun Dun for a mock-serious verdict, or cut to You What SpongeBob when the other person reacts with disbelief.
關於此聲音
This is a short Dutch spoken line, lasting about two seconds, in which a voice says 'Wel beleefd blijven eh' — stay polite, eh. The delivery feels calm and dry, turning a simple request for manners into a gently teasing nudge. It works as a light, good-humoured way to call out rudeness without sounding angry or formal.