No - I cannot imagine me ever sitting on the floor at the therapist's office. I don't sit on floors much in real life - never if there is a choice of not sitting on the floor.

I actually cannot imagine the first one not mocking someone for sitting on the floor. The second one, who is much more flexible, has said sometimes people curl up in balls on the floor. So I have heard of it being done and a therapist just going with it.
Why do you want to sit on the floor?