You are asking for when the party ends, but the party hasn't even begun yet! Either that or I am out of the loop and missed all the signs the past couple of days. Don't get me wrong I believe we are almost there, but let the party fully begin before asking when it ends! If I had to guess though, just randomly I would say bull run will last couple of months this time at least. But that is only because I saw the last run as a test bull run and not a real bull run.
I was confused about the party he/she talking about 
see the current market now? bitcoin can't even pass 10k price point right now even after G20 releasing good statements for cryptocurrency. This might be a really long bearish trend right now. Sad to say but the hype of bitcoin is losing its effect ever since that correction happened in january/feb.
downfall and begin again to see some green, if more people around this chain will continue to give more positive approach more new investors and
traders will start to show up and see the potentials of this asset, after that we will see the party and the bullish run will conquer the market.