If you tugged at me when I was resting somewhere comfortable I would nip you too
We have gone through the stage of Roxy thinking she can sit where she wants. When I caught her where I dont want her to be, sofa for example, I encouraged her to get off and rewarded when she did, although this soon turned into a game knowing if she lays on the sofa and gets off she got a treat so I had to prevent her from getting on with a firm no and rewarding when she went to her own space.
She is allowed on the sofa and only comes on when invited. Can take time but dont give up, she will learn
Matt