in search of constructive feedback plz!!

so i recently got into a relationship with a girl and it’s my first relationship let alone with a girl as well. always have been with guys. i’m so in love with her and she makes me so happy. i just haven’t been able to go down on her and not feel awkward and i just don’t know how to make it sexy. if i could get any helpful tips to help me loosen up that would be greatly appreciated (: