The booty???

My boyfriend was eating me out and then out of nowhere he starts licking my butthole! I kinda jumped because I was surprised and he looked up and smiled then he tried it again.

I know he is going to want to try it again because I mean I didn't say not to, so is there any advice you can give me about it?

How does it feel?

Does it taste gross?

How to check and make sure it is clean enough?