First of all anal sex is practicable in various ways. Either with an anal vibrator, an anal dildo, a prostate vibrator or simply by penetration with the penis.
To start, always use a good quality anal lubricant for sodomy. For beginners there are lubricants containing a product that slightly desensitizes the entrance to the rectum. This product is recommended if the pain of penetration bothers you.
For a personal desire to experience new sensations or the common need of a couple to restore their libido thanks to a hitherto unusual practice.
Due to strong sensation, the sphincter being tighter than the vagina, we feel the cock more in this place.
In order to please your partner, especially if your partner is a man.
In addition to reach an orgasm, as far as men are concerned, the pleasure comes from the sex gland called the prostate. However, as for women, in addition to psychological pleasure, they can feel physical pleasure thanks to the clitoral nerve bundle that joins the anus.