Try it, man. Yes, sucking your buddy to climax is enormously satisfying because you get a real feeling of accomplishment knowing that you have brought him up and over the top and you are rewarded with his man juice, his essential male essence. He has given you a living product of his body.

But licking his asshole demonstrates a level of trust and intimacy that no other sex act does. One can easily argue that a man's asshole is the most intimate part of his body. After all, as soon as he drops his pants his dick and balls are out there for all to see. But his asshole is still tucked away out of sight between his butt cheeks. When you lick him there you are showing him that you trust that it is clean and ready. Do it. You'll be glad you did.