She comes in close again, reminding you of how she loved to dominate you during role-play:
"Oh, does remembering that embarrass you? Is that because I first made you masturbate during one of our role-playing sessions!"
Again you nod weakly, in spite of yourself.
"I remember you got so turned on when I made you break all your old taboos by masturbating yourself! The guilt and shame of it seemed to really add to your excitement!"
You nod weakly; it's all too true.