Yes and no, you need to let them know but not in a way that will hurt their feelings. I suggest strongly encouraging anything you like the next time they are going down on you by moaningloadly or cooing. Then, tell them exactly what you want and how you want it. If they start doing something wrong, say "Do this" instead. You'll tell them they aren't doing it right without being hurtful.
Also, I hate to be that guy but *well*