This is a pretty general discussion, but since your post seemed a little lonely, I figured I'd chime in.
For my partner and I, foreplay is a crucial part of lovemaking. Oral is involved in our foreplay almost every time. We both love the '69' position and although the oral does not take usually take either of us to completion, it definitely gets us warmed up. We usually use a bullet vibe to help her reach her first orgasm in a session, which is kind of interesting since vibrators didn't really do much for her when we first started playing with toys. After she is warmed up with a clitoral orgasm, the actual intercourse portion of our lovemaking is usually focused on getting her to a g-spot orgasm. The whole process is a lot of fun and very rewarding.