Rabbits dig at clothes for all kinds of reasons. For the reasons that Osprey stated and for other reasons too – To get at something that smells good, or to dig out something that smells bad. (not saying you smell bad! LOL, bad could just mean the smell of another animal for example) I know if I’ve been at the beach or I’ve been hiking all day, when I come back Rucy will take great interest in my pant leg, and sometimes dig at it. Maybe if you’ve been out and about, she can smell something that she either likes or dislikes. They also do this when they have anxiety, or if they want you to move, they can also learn it will get them attention.
Floppy, hmmm not sure why she would dig only on one side. That is interesting. Does it matter at all where you are when she does this, or does this happen in a particular position – like if you are on the couch or ?? where one side would be more cramped and she’d want you to move?