Afterglow conversations are good but Rose likes this particular awkward conversation. It's not about the Doctor pulling away from her, or telling her they can't have this. In fact it's about continuing their relationship.

Although she doesn't like that he's leaving now. She pulls her bottom lip between her teeth, collects her jeans and tugs them back up before meeting his eyes again. "Promise, Doctor?" Yeah, she's worried he's going to leave her.