Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you today. I do apologize that your question was not answered before. Different experts come online at various times; I just came online, read about your situation, and wanted to help.
Again I do apologize that my colleagues could not aid you sooner. If you would still like assistance, can you tell me:
How long has she been doing this?
Does she tend to circle in the same direction? Can she go the other way?
Does she seem to be trying to reach her back end? Any scooting or chewing of her bottom?
Are her gums nice and pink (not white/pale)? Moist or sticky?
If you press on her belly, does she have any tensing, tenderness, discomfort, or pain?
Could she have eaten anything she should not have (ie bones, stones, socks, toys, plants, chemicals, human meds, etc)?