Dog biting

[Looseitch]

Hi there,

I have an 8 yr old shih tzu and lately we've been having a problem with her trying to bite when we go to move her. Maybe about a year or two ago she started snarling and growling if someone went to move her from a spot she was comfortable in, which I guess is ok if it was her own bed, but it's the sofa, the arm chair, the bed, etc. Recently it's escalated to trying to bite. She's never tried it with me, but with my parents. I don't know why she doesn't do it to me, but I suspect it's because I never backed off when she snarled at me while my parents did. We have 2 dogs and the schnauzer's never had a problem with this. Any suggestions how to fix this behavior? She's also pretty difficult to train.

Thanks!