In the context of forex auction, it is an exclusive market where only members of the exchange can bid on shares that are short delivered. There are specific windows for the auction market. Exchanges do this to make sure that there is not any conflict of interest.
If you are an individual, you must first be a member of some exchange to participate in the auction market.
The Forex market has the highest frequency of changes between a bull and a bear market due to its massive liquidity and volatility. Therefore, bears have the most trading opportunities in Forex versus other asset classes.