"Not worry about short, shaggy, pale Irish blokes choking to death in my kitchen, for one," Dean said. But he was laughing, and he moved a little too late, ending up with a bit of water down his front, though most ended up splashing onto the floor, and Dean made a face. "You always make a mess," he complained, not sounding at all as if he meant it.
Dean was watching his siblings, and likely wouldn't let it get too far out of hand because they'd just get involved and then he'd have to explain it all to his mum later. But he was happy to see Seamus, and had missed having him to mess about with over the summer. So he wasn't in a hurry to really shut Seamus down. I've seen you with your shirt off - 'sblinding. Like a fish's belly," he teased instead, plucking at his own damp shirt.
Dean reached for a dish towel - wiping at the spilled water quickly and then straightening, whipping the now-damp fabric and smacking Seamus sharply on the hip with it, the towel making that satisfying snap sound as it connected and Dean stepped quickly back out of reach, grinning and glancing back to be sure they weren't being watched by small Thomases who would later copy them.