pleasure

So okay this has never happened before until now and I do t understand. So I'm ready a book that all women read you know what I'm talking about ladies. I hope. And as I'm reading I feel pleasure in my ass. Let me just say I have never done Anal and never will, but I'm slightly confused... Like the confused to the point of laughing a little. Am I the only one that has this feeling? Like maybe not while reading but maybe just engeneral?!