Blow and Draw Technique

Ive seen a few of the top harp players (James Cotton and more) play live and the most noticable thing I see is the cheeks of these guys going in and out like a bellows.  They go from a fully expanded pair of cheeks as to noticable sucked in look on the sides.  Its a massive amout of movement.

Im still a beginner (but improving).  Is this something to be emulated by beginners?  I still do not not get a very good or rich sound.  I have not yet worked on any bending.

Should I be working on this?

Gary K