This trick starts in the same way as a Whip or a Backend Whip. At the moment of the catch, open with a half twist to catch the stick (or the bar on a bar-to-bar rig). The trick is also possible with a Straddle Whip. Making this half turn is possible because of the opening of the trick, doing it on a non-opening trick like a Planche is possible, but harder.
You can find out more about this trick in my books:
Thanks to Maddi for providing a video for this trick.