A 6th grader's recent science fair project was to test if a cat’s butt really touches everything in a home.
The premise was straight-forward: “Does your cat’s butthole really touch all the surfaces in your home?” The boy used non-toxic lipstick applied to long-to-medium-haired and short-haired cats' "bum-bums" to see if they’d rub that lipstick all over the house.
His results and general findings:
Long and medium haired cat’s buttholes made NO contact with soft or hard surfaces at all.
Short haired cats made NO contact on hard surfaces. But we did see evidence of a slight smear on the soft bedding surface.
Conclusion, if you have a short haired cat and they may be lying on a pile of laundry, an unmade bed, or other soft uneven surface, then their butthole MAY touch those surfaces!