I haven't quite figured out why they attack the bedding. If they see me carrying sheets to the bedroom, they come running. As I remove the old sheets, they're on the bed, patting down every moving corner. As I put new sheets on, they're plopped in the middle of the bed, refusing to move. Sometims I just put the sheets over them -- sadly, they love that.
And, don't get me started with what happens when I try to turn the mattress!