I feel that if there is a loss in a long contract, as long as the leverage is not high and the position is not large, it can completely be treated as spot trading. Increase the margin, set the liquidation price to an impossible price, add to the position at lower prices to reduce the opening price, and wait for the opportunity to break even.

Why I say it's hard to short at high positions; the high itself is an upward trend, and going short is against the trend. Many times, just a few candles can bring it down. It's hard to grasp the timing. After a big drop, people want to take a look at the pattern, but the result is that someone picks the bottom and a few bullish candles push it back up. I have never seen anyone who shorted at high positions with Martingale survive for a year; they all get blown up when the market turns bullish.