One big thing you can do at home to get better at this, and many other moves like it is Squat Sit. Literally sit as low in a squat as you can, for as long as you can every single day.
The biggest mistake I see with this move is guys are too fast to actually sit their butt down, and they lose the position. When I do it, I maintain the squat until I literally have the exact angle, my foot tucked under their shoulder, and my hands in the right spot. Only THEN does my butt actually touch down to the mat.
Another huge mistake is guys flopping to their butt quick and ending up too far away: you NEED your hips under their shoulder, lifting it up off the mat; when you're too far away, guys have to forward butt-scoot, or shimmy forward. Again, by squatting, I end up right where I need to before my butt touches.
I squat sit for up to 30 mins at a time, multiple times a day.