This is an interesting question and I enjoy reading the responses here. I see two therapists, one personal for me the other is our couples counselor.
With my T, I sit on a couch and she sits in a chair a couple feet away but always right next too her desk.
Her body language is relaxed. Occasionally she has leaned forward into my space to emphasize something bit mostly she's glued to her chair and sometimes even leaning back. The other day she had a blanket over her to keep herself warm.
I sit on the coach with my legs crossed, usually kind of guarded, unless she has me place the on the floor to do breathing exercises.
Only once she leaned over to give me some drawing tools-and stayed there while I drew. I enjoyed that closeness but that's as close as she's ever come to my side.

Our couples counselor has a love seat we take up. She she has two chairs opposite, and from session too session she'll switch which one asker takes. I think she does this so neither one of us get less attention.