I like to crawl around my bedroom and go upstairs on my hands and feet, but my knees get a little sore after a while. I'm planning on ordering a really cheap pair of knee protectors, the ones they use for playing volleyball. (They were 2-3 dollars, but totally not cute :v)
I'm not much into crawling but when I'm in bed in diapers, I get out of bed by getting myself on my hands and knees (palms down), turning around and heading towards the bottom of the bed, turning around again and exiting the bed butt first. In all, it's about 10 'steps' but it makes me feel little... I think it's the butt first thing that triggers my little side. It reminds me of a toddler backing down a flight of stairs butt first.
I only crawl when my daddy asks me too, and only when I'm feeling really obedient. I typically just walk because crawling hurts my knees, although I'm not terribly afraid to crawl if I could get away with it.