I have a sweet yellow lab dog who has taken to sleeping on various articles of clothing. Always dirty clothes, never clean. Whether it's on the floor, on the bed, or whatever, he always sleeps on a pair of pants or a shirt. Why does he do this? Does he just like the smell?
Mine always looks for either the sweatiest shit he can find or the clean sheets and blankets! So, he's either just nasty or he likes making stuff nasty...or both. Probably both.
He's a kick ass dog, though.
To answer your question: who knows, they're dogs. They're awesome. And they smell stuff in such great detail that you'll never even notice.
You are your dog's master. He adores and worships you. Your dirty clothes smell like you, so he prefers those clothes as opposed to clean clothes.
I hope that is a reasonable explaination.
Now, go clean up your room! Why do you have to have your clothes laying all over the place?
(Sorry about that last remark, I just want you to get a taste of married life.)
My dog does the same thing. He'll go lay right on top of my sweaty running shorts after I throw them on the floor.
Dogs do that for one of two reasons:
1) They love the smell of their owner, and your dirty sweaty clothes do that better than washed and scented clothes.
2) They inherently want to cover up their own smell (as a defense mechanism). My black lab mix will roll over a dead rabbit or any sh!t that isn't dog sh!t (fortunately not dog sh!t). We took her to my parents house one time which is somewhat out in the country, and they have racoon crap way out in their huge yard that she rolled in.