Oh and like Valkyrie said:
Oral sex is part of foreplay and also a finishing technique as well as being different for guys and girls . . .
So a boy should be looking to give the lady about two orgasms during foreplay (shoot for two, settle for one) before entering her.
If the girl did that, shot for two which would mean three total in a rather short duration . . her boy might go into a coma . . . a non-responsive vegetative state . . .
ITs a finishing movement for a guy when he has sadly kind of prematurely dropped out of the race and left her all dressed up and nowhere to go so-to-speak. He has to just drop down and hang-out-till-she-is-happy to make things right
. Bad Boy . . .
If you have to be down there for two long . . . well you are either doing it wrong or the person is not as aroused as they need to be.
I talked to a couple friends that developed a kind of painful lockjaw called TMJ. they went to doctor to doctor and no one could help them. Finally they discovered that it was because they were spending way too much time eating their ladies out(such a graphic expresion eh?).
I mean they liked it and all, packed a lunch and stayed for the day so to speak, but they were in some pain . . .
So the sex therapist taught them the value of extreme arousal . . . and it cut there eating time down by 2/3's with even better end results. Which made them and their GF's very happy I can tell you!
Voila, all the jaw pain and neck pain went away . . . make sure you tell your friend that grind their teetch this little story
.
So to sum up, if you are having pains and dicomfort, you are pobably:
Not there for the right reasons: ITs foreplay not sex.
Not there at the right time: He she is not aroused enough.
Or: You are just not doing it right! Buy some books, videos, porn whatever.