If he told her to jump off the roof of Bart's right, now she realizes that she would probably do it. Which should be terrifying, except for the fact that she knows he would never tell her to do something that would purposely cause her harm. And while he's, himself, hurt her in the past, she knows they were unintentional slights and they are hopefully a shade beyond that now.

So when he tells her her 'lie back' she pulls her mouth from his (somewhat reluctantly) and sits herself on her bed. She looks up at him and a moment later scoots back and lays against the pillows. Her hair is fanned out, her lips are red from their kisses, and her nipples are hard peaks. She feels laid out for him like a meal and then she flushes when she realizes that's exactly what she is to be.