Make sure it is a positive experience for her! Find ways to indicate that you really enjoy it, that she turns you on, etc. If it makes her feel sexy, special and desirable, she's going to want more!

And, here is the rest of the story.

Sex is sex, yet it is more often than not inexorably tied to romance. Romance is an all the time day in day out way of life. If you want to have sex (other than a "Quickie") then you have to make love. If you want to make love you have to begin romancing her. Romance begins hours or a day earlier than the time of the expected outcum, pun, if any, definitely intended.

My point being, if you want her to be wanting more, then you have to do your job and that means to romance her beginning way before you expect to have a sexual encounter.

You do not have to be a great sexual stud; however, you should learn to be a great lover, first, and then work on becoming a "studmaster", second.

Specifically, I recently described an oral technique that works very well in lieu of an actual vibrator. Most boys at one time or another have puckered their lips and blown air through them making the sound of a lawnmower or outboard engine. Do the same by placing your lips against her labia and clitoris. Vary the pressure of the air being expelled and the tension on the lips so that they flap more or less as desired. You can also add vocalization by humming and changing the pitch as you increase or decrease the intensity of the vibrations.

Here is another fact I tell my male dance students: A woman would much rather dance with a man who might be new to dancing, not know a lot of moves, yet can lead what he does know, well, instead of the guy who has been dancing for months or years and is an inconsiderate oaf on the dance floor yanking and jerking with a lead that leaves her wondering and confused about what he is trying to get her to do. In a way, the same holds true here. She would much rather make love with a man who might not know a lot of moves yet can deliver what he does know, skillfully. The rest will come as the two of you continue to explore and learn.

Yeah tell her that it turns you on to make her cum. Let her know that you like giving her oral.

I just joined so bear with me. If you want her to want it more then start the romancing out of bed by becoming a great lover out of bed. A lot of young guys don't understand this yet but as I am older I know women want to be romanced and seduced. It makes them feel appreciated and desired. To the extent that you do this you will have a very eager woman who beg for you to do her orally. My wife had no issues with oral sex because she knew I was ravenous for both eating her pussy and ass. Some women take a long time to cumm from oral sex so you must convey to her that she can take all the time in the world because that means you get to be down their that much more and how lucky you are.