Bulling means that investors are optimistic about the stock market and expect that the stock price will rise. They buy stocks when the price is low and sell them when the stock rises to a certain price to obtain differential profits. Short positions are opposite to long positions. Short positions refer to investors and stock traders who believe that although the current stock price is relatively high, they are not optimistic about the future of the stock market and expect that the stock price will fall. They sell the stock when the price is high and earn the difference.