Giving head ...

So my boyfriend has done everything right . We have great sex , the only problem is I have never given him head . I mean I have done it before with an ex , I just never done it with him. And he constantly asks , but I always get nervous and it never happens . I was thinking about doing something really sexy for his birthday next month . And surprising him with the best head ever . But i don’t know what to do . Help me please ladies .