einen Zahn zulegen

You use this phrase as a verb construction. The verb zulegen changes based on who you are talking to. If you are telling a group of friends to hurry, you say Legt mal einen Zahn zu!. If you are talking about yourself, you might say Ich muss einen Zahn zulegen. It works perfectly for physical speed, like walking or driving. It also works for productivity, like finishing a report before a deadline. Just remember that Zahn stays singular here.

Use this when there is a clear sense of urgency. You are at a train station and the doors are closing? Use it. You are in a restaurant and your friend is eating too slowly? Use it. It’s great for texting when someone is taking too long to get ready. It feels active and energetic. It’s a favorite for sports coaches or bosses who have a friendly relationship with their team. It turns a boring 'hurry up' into a vivid image.

Avoid this in very stiff, formal environments. Do not say this to your CEO during your first week. It might sound a bit too bossy or informal. Also, don't use it for things that require slow, careful precision. You wouldn't tell a surgeon to einen Zahn zulegen mid-operation. That would be terrifying. It implies a bit of a 'rush,' so use it only when speed is more important than perfection.

This idiom is a piece of living history. It dates back to the days of the 'Kesselhaken' (pot hooks) in large fireplaces. These hooks had teeth to adjust the height of the cooking pot. Adding a 'tooth' meant lowering the pot into the heat. Germans love efficiency, and this phrase proves that even their ancestors were looking for ways to speed things up. It’s a deeply rooted expression that every native speaker knows from childhood.

You might hear people say einen Zahn drauflegen instead. This means the exact same thing. Both versions are interchangeable. Sometimes people just say Zack, Zack! if they are in a real rush. But einen Zahn zulegen is the more 'classic' way to express urgency. It’s less rude than just shouting 'Schneller!' (Faster!). It adds a bit of metaphorical flavor to the request.