No one sells a futures, which means everyone is bullish. At this time, the price of this futures will be sealed on the daily limit board, and in extreme cases, the position will be closed. According to the trend theory, you shouldn't sell short. According to the opposite theory, you can short, but observe that when the increase is too big to move, you have to open a short position.

Personally, it is better to do futures with the trend, and there are risks in operating against the market. Just like sailing, it is always easier to push the boat with the current than to sail against it.