I think there's a bunch users already create similar topic about "DCA, only invest that you can afford to lose and Bitcoin history"
It seems there's no new discussion and everyone keep repeating the same discussion, almost everyone already know that and it's nothing need to remind everyone. If they're panic, then it's good since we can buy their coins, if they're not panic, we can't buy the dip lol. So I'd thanks for those newbie who panic and then sold their coins for cheap price.
Like what I reply to similar posts like these, you have to understand it from a perspective of a person who owns hundreds to thousands of cryptocurrencies at his disposal. This implies that the slightest movement of its price could mean a gain/loss of thousands of $$$ on his end. That is why, some people do fear the loss and somehow panic whenever there is a significant drop on the price of BTC.
Bearing this in mind, what could be a good strategy to prevent your cryptocurrencies from dropping its price further? Again, always have a contingency plan. Trade only up to a maximum percentage of a certain value and cash them out as quickly as possible if you see a profit. A 3-5% profit is always better than a 3-10% loss.