Like many of you, I am also struggling with this laceration. I have watched the slow mo vid everyone references around 3000 times, and still have yet to land it once. I think the problem for me (and maybe others) is that the trick is one smooth motion, with no breaks that would allow stopping and starting when learning it, you either get it or you don’t (in my case, always the later I wonder if anyone could make a vid with two people and a dead yoyo, one person guiding the string, making the laceration, and holding the yoyo in air, and the other person showing where to put their fingers and hand to get the mounts right.
This may help newbs like me, or maybe not. But, a vid like this would at least show the trick more broken down than in a smooth motion, which may help in learning it.