Being that you already have control of her masturbation/orgasms, the focus is on her nagging. IMHO, you can't accomodate her desire in the least. It will plant the seed in her mind that if she nags enough, her Master will cave in. This will undermine the D/s dynamic and potentially cause a loss of respect.. maybe not from this singular instance, but if a pattern started developing....

I'm assuming that your orders have been no touching/no masturbating. With her continual nagging, it sounds like this has been going on for a little while. I would entertain the idea of "adding a day" each time that she nags. You've already denied her continually, she knows that the nagging isnt getting her anywhere, but she persists. Once she realizes that each time she opens her mouth about it, it's taking her in exactly the opposite direction that she's hoping for, methinks she's going to shut her mouth, lol. I would use this opertunity to reaffirm to her that you are Master, what you say goes, without question, and the lesson learned will span across other areas of your relationship. You'll still have occasional 'flare ups' from her, but that's part of what keeps it fun and interesting.

Oh, and something to consider if you havent already, I would order her to 'fuel the fire'. No touching/masturbating is frustrating, but if she is allowed to distract herself with menial tasks that draw her attention away, it looses its affect a little bit. Have her read stories, look at pictures, make a conscious effort to think about things that make her hot while she's performing her menial tasks. Unrelenting and continous, utilizing every spare moment of her time focused on things that make her want to touch herself while continuing to deny it.

Just my 2 cents.. I look forward to seeing how you resolve your delimia.. Good luck