Also known as Analingus.  It is a form of oral sex where one partner stimulates the other partner's anus sexually with their tongue. It can also be referred to as 'tossing the salad' or 'rim job'. Rimming, like all sexual activities, carries some risks. Because fecal bacteria may be found on the anus and perineum, partners who perform/give rimming, may contract gastrointestinal illnesses. Rimming can also spread sexually transmitted infections (STIs), such as herpes and syphilis. Partners who like to give rim jobs can help reduce their risk of contracting an illness by using dental dams, plastic wrap, or tongue condoms as well as getting vaccinated against hepatitis A. 

It is wise to maintain good oral health as bleeding gums and lip sores, etc. will provide the opportunity for infections. In the same breath, partners receiving a rim job should ensure they are bathed and cleaned properly.  Another word for a rim job is 'ass licking'. Dominants will often use this activity for their submissives/slaves to show respect, affection, and worship for their Mistress/Master. Rimming includes licking, penetrating with the tongue, sucking, and kissing your partner's bum.  It can be a wonderful, pleasurable act on its own. It can also be a great way to prepare for anal sex and get comfortable and ready for penetration.