Is this common of a dentist?

My dentist is a older woman, about 39 and very attractive, while getting a cleaning done the other day she said she was having a hard time reaching the back of my mouth. She actually threw her leg over me, straddled me and laid her chest on mine and completed my cleaning. She was definitely moving her hips a bit, but could have been just because she needed to move to clean my teeth, she says I ned to come back for another appointment in a few days for something.. But wont cost me as she feels she should have got it this last time, but ran out of time. Is this common?