There are many ways you can go about doing this here are a few favorites!
1. Bite yourself and start screaming blame it on a sib if they say " I DIDNT DO IT!" then you say " WHO DID THEN ITS NOT LIKE I'D BITE MYSELF!"
2. Fall to the ground and start crying if they say "I DIDNT DO IT" say "YA CUZ I JUST PUSHED MYSELF OVER JEEZ!"
3. Leave the sink running with the sink closed and go into another bathroom say "mom can you help me with my hair" if shes downstairs she will go to that bathroom first and see the water if she blames it on you say "IM IN THIS BATHROOM" she will blame it on ur sib!
4. Take something washable like crayones or washable markers and write the sibs name on the wall in there room messey or neatly depending on there age or just how they write. Then when your mom finds out say "how stupid is that writting there own name on the wall."
5. Take something hard and make a dent in your door then say your sibs name and say "WHY DID U DO THAT ALL I SAID IS THAT IM GETTING DRESSED THAT DOESNT MEAN U CAN DAMAGE MY DOOR!" then if they say " I DIDNT!" say "YEAH CUZ I WOULD MAKE A DENT IN MY OWN DOOR!"