I'm trying to learn Norm Stockton's, "The Race". I am new to slapping and had a question. When I'm hearing the muted percussive notes being played in a slap piece, I can't tell if a string is being slapped with the thumb while the left hand mutes the string. Or, if the sound is being created by slapping the left hand down on the strings. Does that make sense? If you are familiar with this tune maybe you can tell me what Norm is doing.