Is it normal to be obsessed with booty

I like ass more than any part of the body when it comes to sex. It makes the vagina feel even better. It doesn't have to be huge (but not flat like Miley's either), just as long as it's soft, feels smooth against my crotch area, and it jiggles/bounces. I think about laying my head on it, using my tongue, and smacking it. I also love when a woman sits in sand too. Or if she sits on her feet, I think thats really hot too. I'm not creepy about it. I keep these fantasies to myself or I share them with a partner. I feel a bit dirty though.