Boyfriend Wants to Eat my Ass

So last night my boyfriend told me he wanted to eat my ass. At first I thought he was joking. Then I realized he was deadass and I got nervous because I was too shy to admit that it was something I wanted him to try. But I toughened up and agreed to try it. How do I prepare for this as far as cleaning goes? I know how to wash my butt, but do I need to do more vigorous cleaning?