What does locking assets mean? How to operate it?

20241204
Total investment 200u, withdrawn 320u, current balance 1015u
Just withdrew another 20u, surprisingly there are people losing money in this market, some even suffering huge losses, and many are veterans in the market, possibly due to greed, otherwise they wouldn't be so reckless.
No one knows how far the market can rise, nor do we need to know, just go with the flow.
In a bull market, I don't short; my strategy is very simple: go long, use light positions, and lock positions, corresponding to big rises, small rises, and declines, broadly speaking.
Even when shorting, always set a stop loss and do it occasionally.
Since I switched to this mindset, I have been consistently profitable. When the day comes that I incur losses, I can use a one-click liquidation or lock position to respond.
Today, my ETH/BNB position occasionally made a loss; I made a couple of short trades on this coin DyDx with a light position and earned a bit of pocket money. It's clear that on the weekly chart, DYDx can still hold; if there's a pullback, I'm also ready to buy a little.