A fiscal interaction between two or more people that is deemed to be of larger proportions than to what those parties are accustomed. It's addicting nature leads to some to refer to it as a 'Gateway Bet,' as it often leads to 'Super Tall Cash', 'Cash of the Largest Proportions,' and 'Bat Shit Crazy Cash.' Besides being a gambling term, it is also used to identify those who are badass, being that, usually, only those types of people will play for Tall Cash
You are about to engage in some sort of competition with a few of your friends. Someone asks 'you wanna play for cash?' You respond 'psshhh... I only play for tall cash bitch.' This let's your competitor know that you only play for large amounts of money, and your condescending tone emulates confidence as well as the mindset of a badass.