oh my, sorry but there's no magic position. You know they're all individuals and I've found that what works with one doesn't work with the next - try a few:
sitting up with you gently holding each paw - this works with laid back piggies and is the easiest! Lying down with you working your way around; someone else holding piggie while you cut; wrapped in a towel with leg sticking out for the ones that REALLY hate it...the list is endless! ...you'll soon figure it out ...... good luck!
We always go for a 2 person job, I normally hold pig while Rach clips. She thinks I have the harder job keeping the victims still however I think I have it easy - I'd hate to be in charge of the cutting, I think that is the difficult bit! I'd cetainly recomend getting someone to hold if you can.
Also the use of food as a bribe, herbs are useful as they take a while to disapear into the mouth... it can provide a good distraction.