Seamus's smile was easier than Dean's, but still not his usual cheeky grin. He sat down carefully, mindful not to disturb any of Dean's things. He sat half-angled towards Dean, their arms brushing, then ducked his head to rest against Dean's shoulder, so that Dean could still see the door. It wasn't really necessary, with as tall as Dean was, but better safe than sorry. "I'm sorry too," he said softly. Just because he hadn't intended to, didn't mean he hadn't hurt Dean. "You know I'd never..." Date Jess, or even pretend to. It would be like Dean dating Graeme, which would be... Yeah, 'creepy and wrong' about covered it.
"By rights, I've got a whole hour off and I've already eaten. You want to stay here and keep me company?" It was a backwards question for what he really wanted to ask. They both knew Seamus would rather Dean stay here and Seamus go back to the pub if an hour was too much.