The worst thing I ever did? Well, my youngest sister was always very sickly. We were told by doctors that she probably wouldn't live to be 12 years old. So, we tried to make sure she never got the punishments meted out to myself and my other two siblings. So, after I and my next in age sister had each already taken a few harsh whoopings for her recently, she did something else that set mother off. As was her wont, she lined up me and the other two on our stomachs over the side of the sofa and meted out numerous lashes with my dad's shore patrol belt – my youngest sister was never included in these group punishments. When no one admitted to the infraction, she made us all go to think about what we'd done with the threat of further lashings hanging over our heads.
So, my sister next in age to me and I bullied our third sister into falsely admitting she was the one who'd done it. Mother made her go out and cut a bundle of king switches and prep them by stripping the leaves off them, then tying them together at the base with some twine. Then, mother made her bare her bottom and striped her buttocks and legs with so many welts that her backside was just red from her hips to her knees. A couple of the stripes even broke the skin.
I hate myself for that every time I remember it.