When you take your roommates sheets and floss your ass with them. Very pleasant when done after a 5 mile run in 85% humidity. If done correctly the sheet will gently clense the top of the ass crack, the bung hole, the taint, and the nuts. Smile with glee as your roommate snuggles into bed and wraps himself in your ass
I got back from football practice and had a good ass flossing with Jim's sheets. -Or- I ass flossed with Jim's sheets and put them back in the dryer.