Note: I am totally against animal cruelty of any kind. These images and ideas came to me after a sleepless night. Insomnia works devilish little tricks on you. Please DO NOT take any of this seriously.
Appear before your crab in a silk kimono holding a bottle of lube. In a suggestive voice, whisper “We’re gonna make sweet love tonight baby!” Watch it side-step as fast as its little legs will allow.
Boil a large pot of water. Have your crab nearby. Periodically look at the pot and then back to your crab with an evil smile. Drumming your fingers on the counter at unpredictable intervals might help hammer the message.
Grab a pair of nail scissors and chase your crab while screaming, “YOUR EYE STALKS HAVE GROWN TOO LONG! I MUST TRIM THEM!! NOW!!!”
Dangle your crab by its hind legs over a tank occupied by a very hungry octopus, while exclaiming, in a loud gangster-like voice, “This is your last chance, buddy!” Be prepared for unpredictable excretions.
Suprise your crab by sneaking up behind him in a giant crab suit with claws that snap, loudly. Takes a lot of effort, but well worth it.
Take your crab out to a nice restaurant. Order crab. Bonus points if you make pleasurable noises while consuming the meal.