You short the bitcoin in a bull market and you will get rekt. Sometimes the indicators also show that bitcoin is going to dump and by shorting it you can get good profit. But as soon as bitcoin start to dump, the buyers jump in and keep buying every dip and push the price up. Its better only to long bitcoin or wait for an opportunity to long.
Of course, I think that's one rule of thumb during a bull market, don't short bitcoin otherwise you will be REKT by the super fast rally, even if you do some leverage. And to counter this, better be a long term holder and just buying during minor dips to accumulate bitcoin overtime. There's no secret here, you just have to really go with the current market situations and you will get profits eventually.