Hello! Your question is simple. A bull refers to a person who is long or long in the market (that is, a person whose price is bullish). A short seller refers to a person who is short or short in the market (that is, a person whose price is bearish). Long call-back: people who are long in the market (that is, people with bullish prices) will eventually sell more orders in their hands; Short covering: People who are short in the market (that is, people whose prices are bearish) will eventually buy their orders. Willingness: That is, the idea represents a trading mentality of floor traders. In the vernacular, the willingness of bulls to take back and the willingness of short covering are: a buying and selling idea of people with bullish prices and people with bearish prices in the market.