I first tried it before I even knew what it was, and when I was still a virgin. My girlfriend and I were both 16. I was caressing her bare backside, admiring her lovely little white bottom and decided to have a peek between her cheeks. Her anus was so little and pink and hairless, so cute actually. And totally clean. I couldn't help but give it a kiss. She just started breathing heavier, so I kept kissing and then licking. It was wonderful.
In the years since I have rimmed all the women I've been with. Only one did not like it, actually she hated it. My desire to touch her butt and eventually to touch her at all disappeared. We turned out to be totally incompatible in many ways.
Basically I think analingus is great if the person you are with likes it too.