"Okay," he said, breathlessly against her lips. With that kiss she might have finally convinced him that she really wanted this, and he wasn't somehow taking advantage. "Just tell me if I do, okay? Or you want to stop, you just have to say."
He bit his lip and shifted; short, audible breaths. His head lowered toward her chest, his hot breath close on her skin, one hand fumbling a little until he managed to guide himself inside her, just a little. His teeth dug into the skin of his bottom lip as the new sensation made him shudder.