Dont worry about 12 volt batteries. Just be sure to NEVER touch both ends of a AA or AAA flashlight battery. That voltage will stop your brain in a split second, turning you into a permanent moron.
Always wear thick leather welders gloves when touching flashlight batteries!!! And make sure to keep both hands in your pockets the whole time.
Just to make my point, this exact thing happened to Donald Trump when he was still a youth. He grabbed both ends of a (more deadly) C cell flashlight battery, and he has never been the same since! He's lucky it was just a C cell. If it had been the most deadly of all, a D cell, he would now be a complete bumbling idiot....