This is an insulting and derogatory description for somebody who is very, very cheap. It's believed that crab's asses are rather compact, so someone tighter than a crab's ass is about as selfish/cheap/greedy as it gets.
Jake: Bill by the way, what did you leave our waiter?
Bill: 15%.
Jake: Christ Bill you're tighter than a crab's ass. I have to stop eating with you if you're going to embarrass me like that again in public. That poor waiter worked his ass off you cheap fuck.
Bill: 15%.
Jake: Christ Bill you're tighter than a crab's ass. I have to stop eating with you if you're going to embarrass me like that again in public. That poor waiter worked his ass off you cheap fuck.
by Space Wrangler August 24, 2021