When they say sing, you sing
If you are taken to a Karaoke bar in Japan, Taiwan or China, and are asked to sing a song, the proper protocol is to give it your best effort, even if you cannot carry a tune. Be careful with special awards. It is considered an honor to be given the fish head at a meal. To refuse it would offend your host. Be gracious, accept the tribute and have a taste. When the focus is no longer on you, it will be taken away.