In American football, a would-be pass-receiver's arm extended timidly, less than full length, because he senses a tackler bearing down on him and is not whole-heartedly eager to catch the ball. Usually plural.
"He's open, it's there.... Oh! Off his fingertips, incomplete. He had alligator arms on that one."
The art of being too stingy to be able to pay for a bill anywhere anywhere... a person physically unable to reach into his pocket to pull out his/her wallet to pay...
Dave attempted to pay, but his alligator arms could not reach into his pocket.... "Yeah, sure I will pay let me grab my wallet, oh man can you spot me I don't have my debit card with me." Fuckin' alligator arms!!