Oh wow that is a cool pattern and I hope he makes it!!!
If you get the pinky back far enough he shouldn't be able to spit it out. I had one that spit it out every time I tried till I put the pinky in as far as I could. Also if he thrashes around a lot once you get it in his mouth you can just keep a hold of him. My guy only constricted once or twice, the other times he just swallowed it.
Just remember that not all bps were meant to make it!