He sounds way too happy about this. Even if he isn't as bothered by it as she thought he was, she really doesn't believe he'd react quite like this.

Is he just trying to act like it doesn't bother him? Somehow, that answer doesn't seem right to her, either. "Really...? I could've sworn you didn't really like having your neck touched..."

She moves closer as she talks, wanting to make sure she doesn't miss anything--and also just because she likes being close to him.