Rimming is the popular term for analingus: stimulating someone’s anus with your mouth. You can kiss the opening or caress and penetrate it with your tongue.
Some people like it when their partner stimulates their anus during lovemaking, while others don’t even want to think about anal sex. So don’t assume your partner will like rimming. Just ask what your lover wants. If you don’t want to talk about it, you may try stroking the anus and then await the response. Body language will tell you a lot.
For some the idea that’s it is dirty or taboo only adds to the pleasure.
Some like rimming better than being penetrated by fingers, a dildo or penis. That’s because the lips and a tongue are extremely soft and moist. Rimming can also be a prelude to penetrating the anus with a finger, toy or penis.
The easiest position for rimming is doggie-style, the one who is licked being on all fours.

How to make rimming safer?