[header] How to cook a crab [title] Freeze your crabs. [step] Place your crabs in the freezer for several hours. The cold air will numb the crabs and cause them to move around much slower. 
This makes it easier to handle the crabs when killing them and may even dull their pain. Remember that once they're desensitized to pain, you should kill them immediately so they don't recover and feel pain again.