The default is FIFO, but when you make a trade online there is an option called the "Lot Selector" and you can choose how many shares you want to sell from each lot you purchased.
You may also be able to automatically change your default to LIFO, if you are flipping and long on a regular basis.
Personally, I prefer the lot selector tool as it helps me determine my profits for the trade.
Trying to stay unbiased, so iHub can be a source for quality information that helps others invest wisely, instead of a place for people to try to manipulate stock prices.