Kyle snorted and then picked up his bag in the classroom. He noticed that the dust he and Siobhan had disturbed made it obvious that two people had sat in that room. He frowned and tried to think of way to redistribute the dust. He decided rather to clean the desks completely, since that was easier than putting the dust back. A few quick cleaning spells later and Kyle was running to potions. He had a stitch in his side as he slid into his seat almost toppling it over. 

"Did you seriously run here all the way from the Library?" Sam asked him under his breath. Kyle nodded. 

"Well you'll be happy to know your butt is filthy." One of the other Slytherins remarked. Kyle dusted off his backside, his ears hot. "What did you do sit on a top shelf?" Kyle nodded again not trusting his voice. He wanted to glance and see if Siobhan had a dust covered skirt. Before he could give her any sign though Slughorn entered the class.