Oh my, I am really about to confess this. Yes. Yes I do sniff my paws. All the time. Did so ever since I was a kid. Part of my OCD regimen. But yeah, it doesn't have to be because you touched something nasty or anything. I don't really know what it is. In third grade, one of my teachers thought I was picking my nose. She said, "stop picking your nose," and I told her, "I'm not... I'm smelling my hands!" She said that was silly and that no one sniffs their hands, but then ten other people in the class said, "Yes, she does... she has since first grade!" Actually, I started before that, but went to a different school for kindergarten. Anyway, she wasn't a great teacher.
A funny side note: In my first grade year, our class put on a play which was a Beatrice Potter story about Peter Rabbit. I played either Flopsy or Mopsy... can't recall. I am up in front of the classroom, in front of friends and parents, acting all bunny like and trying not to sniff my paws. I was not successful. My parents were shooting the event with our old Super 8 camera. When they transferred the movie reels to DVD a couple of years ago, my mom asked me what song she should put the scenes from the play to (all the Super 8 film reels were devoid of sound). I responded, without a second thought, Lynyrd Skynyrd's "That Smell." That DVD is the single most disturbing thing anyone could want to see, but it is hilarious!!!