Advice on going down on a girl?

AJ

I don’t know how to get over the intimidation of it all. I don’t go down on my girlfriend and I feel bad about it. It’s always just her pleasing me and I try to get her off but I get uncomfortable and don’t know what to do so I don’t. She doesn’t get upset with me, but it’s only a matter of time since she’s putting in more effort than me when it comes to sex and honestly most aspects of our relationship.