I'm answering for my boyfriend, he prefers vaginal and does not ever want to try anal. We have taken too many anatomy and science classes to know what's in that hole and that it simply wasn't made for that. If he ever wanted to try it, I wouldn't go for it. I'd first ask him if I could use my dildo on him and if he is okay with that then we might be getting at something.
I also feel like if I were to try it he might learn to prefer that hole over my vagina...I don't ever want to have to deal with that.