Why can’t I just do it??! (Giving head)

Okay, so. This is quite embarrassing to admit because there’s a lot of people who would just say things like “put your big girl panties on” or “a real woman would”, but... I have a really hard time giving my man head. Everytime he try’s to get me to do it I feel so bad because I can never work myself up to it. I want to do it and I know once I actually get it in my mouth I’ll be good to go it’s just the action of getting to that point that I struggle with. I get so anxious about it and I don’t know why. How do I overcome that mental block and just do it?? Ughhh.