[drewitgolf]

Extensor action is simple if you use opposing pressures. The right index finger and thumb provide the outward push and the index left finger and thumb provide the inward pull. The opposing pressure of the right index finger and thumb is slightly stronger as you perform the back swing.

For the down swing in swinging the left index finger and thumb pull down plane and the right index finger and thumb push up plane. The left index finger and thumb is slightly stronger as you perform the down swing.

For the down swing in hitting the right index finger and thumb push down plane and the left index finger and thumb push up plane. The thrust from the right arm straightening is added and over powers the up plane push of the left index finger and thumb and provides the hitters release. This action also makes a slow start for the hitter a piece of cake.

This is more about grip pressure than Extensor Action and IMO not necessary.