Is there any chance that developmental issues are at play here? The vast majority of children learn to wipe early on because the lack of hygiene is uncomfortable. Barring developmental issues, could there be environmental factors, like something in the toilet paper being irritating to her skin? Outside of that- I'd inform your parents if they don't already know. Hopefully they'll make her do her own laundry and clean the bathroom every time she leaves it that way until she gets the point.

I know the struggle. My 11-year-old sister doesn't even close the door after she had pooped! I hate it!!

my sister does that too and she's 13. kill me.

Time for the saran wrap across the toilet trick.

j esus. have you talked to your mother about this? not wiping is beyond gross and unsanitary.

How can she not wipe and your parents don't do anything. I should think the school or her friends would notice that. yuck