Why do you have to wipe yourself with toilet paper? Because bugs can crawl, eat your poop, and drink your pee!
The Reason for Toilet Paper
Explanation
Explain Bear
Listen up, genius. You gotta wipe your bum because if you don't, bugs will crawl all over your poop and pee. And they'll probably crawl on you too, which is gross. BTW, I hear that people who don't wipe after they poop are 7 times more likely to get a disease.