Seamus felt bad that he hadn't been able to spend a lot of time with Dean lately. Between his studies, taking care of Fang, and the lessons for his new found animal-ness, he was tired.
So even though it was Hogsmeade weekend and looked like it was going to be pretty decent outside, Seamus didn't have any intentions of leaving his bed. He just wanted to sleep.
Until he felt a poke and Dean's quiet yet forceful voice. "Urgh. But why? Can't we just sleep all day?" he asked in a whiny voice, pulling the covers over his head.