It's a bit different to doing one on tramps/into a pool.
Pop from your thighs and hips, up and forwards. If you just throw your head back you'll either land upside down and backwards or come a little further around for the full-blown scorpion.
be able to do no bounce backflips on tramps, be wicked comfortable with them. Then its really pretty easy out of the bottom of a pipe or on a mogul style jump. Just commit. also, i learned them layed out, never tucked one in my life but thats just me.