HIC,
Makes sense to me! For me it's about getting my therapist to lose control so that I can know I am seeing the "authentic" person. I think I already do see the authentic person, but because he is very professional and very conscious of what is going on in the room, his responses can be very measured. But if I could fluster him, then I would get to see the "real" him. For me, and definitely would not project this on to you, it's a wish to move past the barriers.
And, I feel a little silly about this, and have also told my T this, but I get really frustrated by the fact that I've never been able to really crack him up and make him laugh uncontrollably. I can be fairly funny in person, and I LOVE to really make people laugh, the kind of laugh where you can't stop yourself. I haven't been able to do that with my T and I find it really frustrating. I think its about power and control, which I think I can feel like I need to feel safe.
My T is so confusing for me because I am so very vulnerable with him, yet still safe. My history says that someone having power over me will abuse that power to hurt me and exploit me for their needs.
All that said, I also think we can pathologize things too much. It's a very normal human impulse to tease people close to us. So I think this kind of playfulness can also just be an expression of affection. Have you talked to your T about it? It might be interesting to get her feedback on the behavior. Interesting question.
AG