I had a girlfriend in college who was sensative like that, but insisted on receiving multiples. So we decided to purchase some light bondage equipment (soft rope, etc.)
She let me tie her up the best I could, especially behind the knees to keep her thighs parted wide open. Last thing I ever wanted was her legs clamping down on my head whilst "working downtown."
Then we decided on a safe word that would only truly be used if she was experiencing pain of some sort. Any other reason wasn't allowed.
Then I went to town, quite literally. As intense as it was, I just kept it up (hehe, another pun). "Working" includes trying other areas and techniques so that one area doesn't get overworked.
Do you know where your G-spot is?