Avatar Pose and rotation lock, But still allow Head and hand tracking

I’m sure this is a very simple setting that I am overlooking, but I cannot for the life of me find it, But I would like to be able to toggle into a position (for example, Laying down) and keep the body from rotating when I move my head. Basically the exact same settings that are used when opening the vrchat menu, as it locks your body in it’s current pose, but your head and hands are still free to move without affecting the body. Can anyone please help me to figure this out, it doesn’t seem there are any tutorials online for it and I asked in the discord forum, but still no dice.
Thank you.