I don't know what your T is like, but I don't think your fear or insecurity is insulting to her. Some things I can talk about quite openly, even if they might be embarrassing. Sex is not one of them. I feel totally humiliated, even if I know everybody else has the same feelings, or does the same things. It doesn't matter, I can barely spit the words out. Part is just embarrassment, part is that I'm terrified of what other people think. I am scared to death of their reaction, or what they will think of me. I feel totally ashamed. It doesn't even matter that I wouldn't think much of it if someone told me they felt, thought, or did the same things. I feel terrible saying it myself. Anything sexual is very intimate and touches on the most secret parts of who you are. It's natural to be scared. By telling your T you are putting an immense amount of trust in her, in a way that you have not before. She probably understands that.