请慢用。

You use this phrase when you are the one providing the food. This could be a waiter serving a dish or a host placing a plate on the table. You say it right as the eating is about to begin. It is a standalone phrase, so you don't need to add much else. Just a slight nod and a smile will do the trick. It makes you sound incredibly cultured and respectful.

Use it in any setting where food is served. In a restaurant, it is the gold standard for service staff. At home, if you cooked for friends, saying this as you set down the final dish is a lovely touch. Even in a business meeting with catered lunch, it signals that the work can pause for a moment of enjoyment. It is the universal green light for 'let's eat.'

Do not say this if you are the guest. If someone else cooked for you, saying 请慢用 makes it sound like you are the host. It would be like walking into a friend's house and telling them to make themselves at home! Also, avoid using it if someone is clearly in a massive rush to catch a train. In that case, 'slowly use' might sound like a sarcastic joke.

Chinese culture places a massive emphasis on the pace of life and health. Eating slowly is traditionally seen as better for digestion and a sign of a refined person. In the past, 'using' something was a polite verb for consuming or experiencing luxury. By combining 'slow' and 'use,' you are wishing the person a healthy, luxurious, and peaceful experience. It reflects a culture that values the social bond of the dinner table.

You might hear 慢点吃 (màn diǎn chī) among close friends or family. This is the casual, 'cool' cousin of our phrase. It literally means 'eat a bit slower.' If you are at a very fancy banquet, you might hear the even more formal 请大家慢用. However, 请慢用 is the 'Little Black Dress' of Chinese phrases—it fits almost every occasion perfectly and never goes out of style.