The term bubble refers to that stage of poker tournament where all the players still standing are certain to win a prize. When there are just a few players left to be knocked out of the money, many people play very cautiously to ensure a profit from the event.
As we know from the stock market, the best way to make a profit is to buck the market sentiment. Thus you should play with greater controlled aggression at this stage of a poker tournament. You want to increase your stack. The idea of a tournament is to win big, not just get little more than your money back.
