Denny Prokopos starts in a butterfly guard, with an overhook grip and an underhook to the other side. He scoots his hips towards the underhook side to break the opponent’s posture. He then makes use of this opportunity to wrap his arm around the opponent’s neck.
Here’s when it gets a bit tricky when he connects his hands. He starts to demonstrate what he calls a “pretzel grip”. The pretzel grip makes use of the ulna (the lower bone in the forearm) instead of the radial bone. From the pretzel grip, he teaches to drive the hands towards your sternum and then lift the elbow up.
Another detail is to free his leg and place it on the opponent’s back as he finishes the guillotine. If the opponent isn’t tapping with the squeeze, he mentions to crunch and connect the hip and the choking arm’s elbow.
In the latter part of the video, he showed how to set the guillotine from standing. Starting with an overhook, he steps on the outside of the hip to shrug on the whizzer side and break the opponent’s posture. He then proceeds to wrap his hands for the guillotine, pull up and turn towards the choking arm’s side.