Betting or risking everything you have, except for your essential clothing.
Origin:
The phrase likely originated from the idea that a person, in a desperate gamble, would bet everything they own, including their clothes, except for the buttons that hold them together. This emphasizes the extreme nature of the bet, where the gambler is willing to risk absolutely everything.
Example:
"I'm going all in but buttons on this hand. It's my last chance."
Note:
While the phrase is commonly used in gambling, it can also be used figuratively to describe any situation where someone is willing to risk everything they have.