Dean was used to enthusiastic greetings - coming to his mum's house as soon as he'd gotten home and having his mum and his sisters all jump him had been good practice. Except there really wasn't good practice for having a fully-grown Irishman tackling and wrapping himself around you in his hallway, and so that Seamus didn't fall over, Dean had to hold him up - ended up with his hands on his ass to keep him there and laughed shaking his head and stumbling into the flat that way.
He couldn't see, of course, past he Seamus-shaped bulge in front of him, but instinct gravitated him toward where he hoped a couch shoud be so he could dump his best friend onto it.