1. I held the pick close to the outside edge of my thumb (using a sharkfin, the rugged edge).
2. I then plucked the string with the pick and my thumb seemed to lightly graze the string.
3. I cool squeal came!
Does this sound right? Ive been playing for 4 years now but I have only been trying to learn lead for the past year. So sorry if I seem daft!