What's the exact meaning of "hunker down"?
May it be for istance, when there's an earthquake and everybody goes under a table or in a secure location bending down on his kneels to protect himself?
Can you do any example using this verb, please?
It doesn't have to suggest a specific pose. It means to retreat to a place of safety and stay there until the danger passes. It can be days, so you would not be in the same position the whole time, obviously.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.