The best part of sex, in my far-from-humble opinion, is the pleasure you can cause in your partner(s).
While being stimulated by your partner is certainly far better (for most people, if their partner's any good at
it) than masturbation, it is still pretty much the same, only better.
Going down on a lover, on the other hand, allows you to get a kind of pleasure that you cannot give yourself, even
in part; the vicarious or empathic response you get from their reactions.
The techniques here, therefore, are centered around cunnilingus, including (since there's no separate name) using
your fingers. Along a similar line I've now written Advanced Fellatio Techniques and Secrets. This was learned
as a subject, not performer, but with the same quality of skill involved. Because of the number of questions I
received on the subject, I also have Advanced Anal Sex Techniques, for those who want to know about that.