Eatting ass

soo my boyfriend wants me to eat his ass lol there's no other way to say it. He said he saw it in porn and would like to try it and I'm honestly down to try literally anything once as long as I'm comfortable with it.  it's just... idk how?? like how does one... eat ass?   

Edit: Those who are telling me not to... just don't respond on the post . I want to do it. I enjoy trying new things in the bedroom and I ask how to do it, not your opinion on it thanks

UPDATE: alright so I did it and he REALLY enjoyed it. Like a lot. And honestly him being so turned on turned me on and i enjoyed doing it. He was fresh out the shower when we had performed the act. I was a little nervous on how to go about it but so was he and once I started he was moaning and he had precum dripping. So overall a 10/10 experince. Thanks for y'all help