The stupidest thing I have ever done...

When I was about 17, we (me and my younger brother) were checking the play on the rear gears on a differential (on the car). My brother, being 3 years younger, didn't know much about cars. I held onto the ring gear to feel the amount of play between the pinion and the ring gear and asked my brother to gently rotate the axle back and forth out where the wheel bolts onto. He grabbed the axle flange and gave it twist and sucked my fingers in between the ring and pinion teeth. DAMN right I Yelled!!!! Those damn gears had no respect for my fingers....it was as if they had sucked putty between the pinion and ring. Blood...YES!!....Pain, YES!!! Couldn't blame my brother, he didn't know any better...BUT I SHOULD HAVE KNOWN BETTER!!!!