When drawing from the SOB position, you need to avoid the tendency to start bringing the muzzle forward before it has cleared your body. This is sometimes referred to as "sweeping your body".
Start by standing in front of a full length mirror with your unloaded holstered weapon and slowly draw, watching your muzzle through the draw. Have your off hand by or on your stomach ready to engage your shooting hand and weapon while still close to the body and before full presentation.
Do this over and over until you can develop a smooth presentation then work on your speed!
Practice practice practice!
