Rinse the live blue crab with cold water to get any gunk off them. To avoid getting pinched, use tongs to rinse the crab under the kitchen faucet.
Fill a large saucepan with water - enough to cover all crabs. Add the package of Louisiana crab boil seasoning. Bring the water to a boil.
Add the washed crabs. Cover and allow to cook for 10 minutes, until the crabs are nice and pink.
Turn off the heat and allow the crabs to soak in the seasoned water. The longer they sit in the water, the spicier they will be.