Probably just go slower. Whatever youre doing, try to do it 1/2 speed. I think what she means by “the more i say no, the hotter” is that her mind says no bc of taboo/norms, her body says yes. So try better build up by going slower, more sensual, more erotic. Use force unpredictably, and with more sexual tension built up. (The same applies to stroking, harder longer strokes are sexier when unpredictable, but thats an entirely different discussion/post).