I think we would have to get a lot of rich people involved. And do some high leverage dumping to get the price moving down.
That is right, bitcoin price manipulation needs a lot of money to do because if you are just an average person then you can't manipulate or even move the price. Some of the people doing that established a group that they have accumulated funds from each other and they manipulate the price of bitcoin depending to their desire.
With a huge funds and every people can pumping the price of bitcoin a lot and then make the market fomo about bitcoin and just instantly to dump all of your coin on the higher price.
But i think if that needs a collusion between the traders. Just a huge whale can manipulate the price of bitcoin