Disclaimer: How many times do I have to do this? Maybe I could just write a disclaimer for all my fics. Maybe. Anyway, don't own. Bugger.

Different stages of Sasuke's sleep has different poses. At least that's how Kakashi sees it.
When he first gets to sleep he curls up at the edge of the bed, as far from Kakashi as possible. He's fallen off before. During this stage Sasuke has the blankets. Kakashi has to freeze during this. Thus he has taken to stealing the blankets back when his student starts to fall asleep.
The next stage, he sprawls on his back. The first time this happened Kakashi got hit in the face by a wayward hand. Sasuke denies it, but Kakashi swears he did it on purpose. During summer when Sasuke just wears boxers to bed, this causes problems for Kakashi. He finds it hard for him to keep his hands to himself. Kakashi thus admires his self control and promises to take it out drinking.
Kakashi has the blanket now, refuses to give it back. He who has the blanket has the power. Or so he thinks. It isn't till a few minutes later that Kakashi realises that Sasuke has stolen the blankets back. He groans at the thought that he goes through this evey night, you'd think he'd be used to it.
Subsequently Kakashi should be getting cold. But he isn't, and even if he was he wouldn't say anything. He's staying warm becuause Sasuke's draped over him pretending to be a blanket for him.
It's about now that they tend to fall asleep. Sasuke comfortably passed out on Kakashi and Kakashi sneakily getting groped.
Wait. Groped. That's not a normal occurence. It's about now that Kakashi comes to the conclusion that maybe Sasuke isn't as asleep as he thought. It's with that thought that Kakashi makes the mistake of looking at Sasuke. It's also about now that Kakashi finds the note from his self control, something about a holiday.
Afterwards he's not complaining, but he does wonder why he had to have the molestable student.