In most books and DVD's I see the Glide is taught using the left-fingers to do the action which I found quite difficult. I instead used my thumb which seems to work much better. I'm here to ask is there a reason that it's always taught with the left fingers? Is there any specific reason that makes the fingers more suitable? And also I want to know if anyone else does the Glide with their thumb instead of fingers. I see it as a matter of preference, but there may be a deeper solution within this. Please reply.