RE: How do you release?
I feel what he's talking about is more the push/pull which will trigger you release using back muscles. Pushing the pin toward the target while squeezing you back muscles/applying back tension to release the release.
There really is little push involved and more back tension applied. This is the proper way to release all releases be it a "true" back tension release to thumb, pinky or index style releases. You should never just yank the trigger.