Another thing I do when supporting it under the axles is to leave the wheels and tires on if you can and work on one side at a time.
That way if it does fall, it won't fall all the way to the ground and crush you. It will fall on the tires and give you a chance of surviving.
If I take a wheel and tire off to work on the axle or something, I lay the wheel and tire on the ground under the drum or rotor so that it falls on it instead of all the way to the ground. Try and keep body parts from between what you are working on and the ground.
I also leave my floor jack under the pumpkin or axle tube when up on the jack stands if possible.
79' CJ7 - 82' CJ8 - 94' YJ - 96' ZJ
Diagonally parked in a parallel universe.......