The 2021 Bitcoin bubble has popped and the technicals indicate a downward trend. I think the recent Bitcoin rally to $40K is just another example of a bear market dead-cat-bounce.For investors who are thinking of shorting the Bitcoin bubble should think about entering around the $45-50K mark.If Bitcoin passes the $45-50K resistance with strong momentum, I think Bitcoin bulls will start re-entering and bullish momentum may continue for the foreseeable future.My target price for my short position is $30K and $20K, where I will cover my shorts in tranches.In order to trade a speculative bubble like Bitcoin, understanding the technicals is almost important as understanding the fundamentals.