All the snappers I've ever kept have gotten to be at least somewhat tame. The vast majority of them were much quicker to try to kick their way free when being held, as most turtles will do, than try to bite. I've been told that softshells are far more likely to use their jaws when held, but I haven't kept them so I can't confirm this.
Hold them on the back lip of their carapace, behind their legs.
And when it gains weight make sure to not (or ever) pick it up by the tail.Could cause spinal injuries.
o..... i always see people pics of people picking up there snappers and they didnt look too happy...... for me the first time it would try to bite me i would be afraid of it..... lol dont want to lose a finger or anything..... but again thats just me