Through your anus you can reach your prostate, a small almond-shaped button that hides behind the base of your penis that when stimulated properly leads to multiple orgasms similar to those experienced by women and the ability to ejaculate without needing to be erect or touching your penis.
Enjoying it depends largely on preparation, both mental and physical.
The pain of anal sex for men comes from not being prepared, fear of judgment and nervousness, which tightens your sphincter, the ring muscles which guard your anus. When your prostate is properly excited and played with you can discover a whole new level of pleasure that can only be described as mind-blowing. There’s also great pleasure that can be derived from outward stimulation of your anus hole, or rimming, which is pleasurable but doesn’t lead to the orgasm you can experience from prostate play.