When steaming crabs, it is best to steam them in bundles, which can prevent crabs from struggling to kick off their legs during steaming. You can also kill or stun the crab and put it in a pot for cooking: before steaming, cut a knife at the tip of the crab's navel and stick it hard with the tip of the knife, so as to avoid the crab struggling to get its legs off, and the crab's legs will not fall off and yellow will not flow out.