Bottom Deal is a very famous gamble sleight of hand in magic . This technique helps the magician to deal the bottom cards instead of the top card.
Bottom Deal is rarely used in card magic, it is often a technique to “show off” between magicians. The reason is probably because it is a trick derived from gambling and partly because it is quite difficult to implement.
The card tricks that use the Bottom Deal are usually ACAAN and Gamble Demonstration.