I can understand where this Kid is comin from...........I tohught it was damn near impossible first time I ever tried it. Heck I still have trouble doing it.......LMAO!
But like all things,it just takes time to master. I have found that if you hold the pick as close to your thumb as you can,and instead of hitting the string with the side of your thumb, instead try picking it with your thumbnail afterwards it gives off a pretty unique squeal. Hope it works for you!