In this video I show another very important drill that emphasizes the transitions from Knee On Belly to Knee On Belly and then from Knee On Belly to Mount.
These transitions are very important and very few people actually practice them. I encourage you to practice this transition a lot as it will help you flow from dominate position to dominate position.
Once you have gotten this transition down you can add in some more advanced transitions. There are a lot of different ways to transition and control while in KOB.
For the people really trying to build this fluidity of movement I suggest doing reps on a heavy bag. If you have access to one all you have to do is lay it on the floor and practice just like it was a training partner.