hunker down

Since you asked:
hunker down

Nobody seems to know exactly what its origin is, though it has been suggested it’s linked to the Old Norse huka, to squat; that would make it a close cousin of old Dutch huiken and modern German hocken, meaning to squat or crouch, which makes sense. That’s certainly what’s meant by the word in American English, in phrases like hunker down or on your hunkers.

The Oxford English Dictionary has a fine description of how to hunker: “squat, with the haunches, knees, and ankles acutely bent, so as to bring the hams near the heels, and throw the whole weight upon the fore part of the feet”. The advantage of this position is that you’re not only crouched close to the ground, so presenting a small target for whatever the universe chooses to throw at you, but you’re also ready to move at a moment’s notice.

Hunker down has good onomatopoeia. Overtones of the word "chunk," which is a verb in the south, meaning to throw something like a hunk of debris.