Jane, my T has also blushed, and is pretty shy actually. I know I have made him uncomfortable a couple of times. I brought it up and we walked about it. He acknowledged that he's shy and certain topics are a bit harder for him, but he assured me that the topics are important and he can handle his own discomfort. He also apologized that his discomfort was apparent. Also, as time has gone on, I have noticed that his discomfort has lessened and we can discuss those topics pretty freely now.

Ts are human and have their own issues. If they are competent at what they do, they know how to put it aside (mostly anyway), and deal with the discussions anyway. If you are concerned, maybe you could discuss it with him. Having that discussion was helpful for me anyway.