Mach A and Mach B drills

I HAVE SCOURED THE GLOBE in search for the treasure trove of rare info concerning mach a and mach b drills and have come out empty handed. I have turned to you my friends and the wisdom of charlie francis as my last resort.How do you do mach a and mach b drills?

I believe kenny mac posted video of A’S and B’s on the old forum. Kenny do you still have those videos?