(idiom) to hit someone who is already down; to crush a defeated or defenseless enemy without mercy

(xiehouyu) like a dog that fell into the water and just climbed out, shaking its body to dry off; used to describe someone shivering uncontrollably (e.g., from cold or fear). The pun relies on "qióng dǒu" (literally: shaking incessantly or miserably)