I've been told that too. I think it's because sucking cock is my all time favorite sex act. I like it even better than being sucked of (although that's a good second), mainly because I can do it more often. When I was younger and slutty I once sucked off twelve men in one evening. There is no way I could come that many times myself. Because I like it so much I really put my heart and soul into it.

But the question was is it natural or is it a learned skill. Probably some of each. As stiffun said, some really enjoy it and their enthusiasm shows and others are just going thru the motions. And like anything else, the more practice one has the better he gets.