Hole carding is a cheating technique used by players to gain an advantage over the house by secretly peeking at the dealer's hole card, which is typically hidden from view. By observing the dealer's hand, players can gain valuable information about the cards that have been played and make more informed decisions about their own bets and plays. This can help them identify favorable situations, such as knowing when the dealer has a weak hand or is more likely to bust, and make more strategic decisions to increase their chances of winning.