I think he’s talking about the slide release. On a Glock or his VP9 you can hit the slide release with the thumb on your firing hand. With my 1911 I just hit the slide release as I roll my support hand into position.
Based on Front Sight, the slide release is only supposed to be used if the mag and chamber are empty. The slide will remain locked back if you try to rack an empty gun by pulling the slide back.
Instead, pull the slide back to rack/close it. Their method is to not let the slide slam full force when letting it go forward. Nor do you ride the slide all the way forward with your hand on it. Instead, let it go about 1/2 way so it chambers the round and closes all the way forward, but without the nearly-full force of a completely compressed recoil spring.
I've read some articles that say you should count using the slide release in your "rounds fired" total if you're keeping track, in particular if you're dry firing, since the force created by doing that is causing wear and tear on the firearm similar to firing it. Not sure I agree, but seems logical.
The bottom line is, it doesn't matter where the slide release is located if you don't use it much.
