A kick roll is a very fast repetition of kick drums usually achieved by a real drummer by using two kick drum pedals. Of course on a drum machine or sequencer, you just tell it to do a heap of kick sounds in a row. So how do you do it with the mouth? This is the easiest method to learn.
Standard Beatbox Notation (SBN)
{ B d }
Method
Practice doing the Dry Kick { d } with your lips together so that the sound is forced through your lips. This creates an oscillation. You'll find that it will start to sound like the Classic Kick { B }. You then need to alternate between the Classic Kick and the Dry Kick { B d B d B d B d }. The easiest way (but not the only way) to put it into a beat is to follow the roll { B d } with a single Classic Kick like this: { B d B }.