lower your head
The German phrase 'senke deinen Kopf' is the equivalent of 'lower your head' in English. It is used in the imperative form to instruct someone to lower their head, often for safety reasons or as a sign of respect.
Please, lower your head when you go through the door.
This sentence is used to give advice when a tall person should bow a bit not to hit their head on the door frame while entering a room.
To show respect, lower your head when you see the teacher.
This statement is representing a cultural gesture of showing respect in many countries where students may slightly bow their head to acknowledge their teachers or elders.
Lower your head if you want to safely pass under the branch.
This sentence is giving a suggestion for any situation where someone does not want to hit an obstacle such as a tree branch. Lowering the head in this instance is a physical action to avoid an obstruction.