Hold em uppaside down by the back legs with your left hand. Slice the scrotum with two vertical slits in the rear about the size of half the testicle. Squeeze em like a pimple and when they pop out grab hold and pull. Add stop leak and tetanus shot. The hardest part is catchin em.
That's pretty much how I remember it from about 50 years ago working on a KS hog farm one summer. The catching/holding part gets even tougher when the farmer has let them go a little longer than he should have and they have put on weight/developed more muscles.