There’s a Tucker Max story wherein he decides to have anal sex with a woman while his friend secretly films it. As it’s happening she suddenly defecates on his dick and he throws up on her. His friend spasms laughing and falls out of his hiding place and she screams and runs out, butt naked covered in shit and vomit.
Now, first of all don’t ever film someone without their consent, obviously. Otherwise, I have personally never had any sort of fecal accidents in anal play. Every now and then the receiver, the woman I’m anally having sex with or myself getting pegged, has to stop and then go to the bathroom, but there is never any issue with it being so loose.
Here is overall what I recommend in terms of a clean and pleasant anal experience, whoever is the receiver.
Women usually do this anyway but men: consider shaving the hairs around your asshole. Analingus and pegging will be both more fun for her and you will have cleaner dumps and no dingleberries.
Between the last defecation and the anal play the receiver should wash thoroughly, with soap, all the area around the asshole as well as inside, try to get soapy water inside to clean it well. Some people perform enemas.
Avoid spicy food and dairy the day of the activity.
During the play, have a few towels under the activity to minimize lube and other juices getting on things, as well as your hands for drying after applying lube. Have some paper towels around to clean anything needed or hold used anal toys.
Make sure to wash all used toys thoroughly and both participants of the anal play afterwards. After performing analingus, a person should rinse his or her mouth with mouthwash or, if unavailable, toothpaste.