This is a slick transition to the X-Guard from the B-Fly Guard. In the video Eddie Bravo goes over the transition a number of times in depth.
He starts out by explaining that when your opponent stands up when you are in B-Fly that they are giving you an opportunity to transition.
Once the X is on you can easily sweep your opponent to get the top position as Eddie shows in the video. You can also transition to lower half positional fighting if leg locks are your money subs.
