Catch guy friend watching you sleep. Don't know what to think of it. Help?

Had some friends come over to my apartment, and because my apartment is small, one friend takes the couch and me and the other(the one in question) take the bed.

I wake up to some form of pressure on my forehead (the pressure radius being small). Once I wake up, I see my friend staring at me. A few seconds later he pats me on the cheek, turns over and falls asleep, only saying "alright."

I am so confused as to what just happened. And I can't really ask him because I know he will just deny it. Is this a good thing or a bad thing? To Guys: Why would you do this? Thanks