Blue grabs is where you have a fungal infection which grows on your toenail which grows in your mouth( teeth and tongue) instead.
blue crabs is where after you suck on someones toes because you have a foot fetish and they have a fungal infection on there toenail the fungal starts to grow in your teeth on your tongue
av YELLOWDOG1996 6 april 2010
1 more definition
When a female squeezes and twists a man's balls till they turn dark blue. Then the male prepares for intercourse by clamping his hands like a crab.
"I was in the mood for sushi, so Sarah gave me a Blue Crab."
av calry 22 april 2007