Suggestions. Please

Ok so me and my boyfriend has had sex numerous of time and he never gives me head but he just came around to it he had went down twice and both times he's down there for 30 seconds or so and then comes up and says I don't know how to do this ... And I feel so awkward. Tbh I've tried what I have tasted like and it's not very tasteful at all to me it taste salty and bitter ? and I think that's why he won't last long down there and I'm really insecure because i want him to go down there and it taste good. Any help/tips on how to get a better taste ?? Any reason why it's like that ???