The equivalent to the British afternoon tea is the German Kaffee und Kuchen (coffee and cake). This ritual is common when visiting, let’s say, the parents of your recent girl/boyfriend for the first time. It’s slightly formal and usually occurs sometime between 15:00 and 17:00 and the combined sugar and caffeine rush is enough to cause insomnia for several days.
Sometimes Kaffee und Kuchen might extend into the less formal Bier und Abendbrot (beer & snacks/sandwiches), particularly when the conversation is going well. This should be considered as a good sign if you’re visiting your partner’s parents.