I am struggleing to learn how to slap. I bought the Ed Friedland Slap DVD a few days ago. I've been practiceing daily. I am having trouble hitting every string,except the E string, cleanly. I am hitting every thing with the A the D and the G. Is it just a matter of practice or is there something I should know. I seem to have some success with a bit of muting on my right hand. Is this the proper technique?