I've been able to talk about sexual issues and topics with my T, even though I had lots of trouble doing so with ex-T and ex-MC. I think it's because he's very matter-of-fact about it and talks about it just like it's any other topic. Like he can just say stuff like "masturbation" without batting an eye, where I tend to use euphemisms for things. (Though I did manage to actually say that word to him recently.) It took some time for me to get to that place, but I was also able to tell him something related to sex that caused me a lot of shame--his accepting and nonshaming reaction to that led me to feel much more comfortable bringing up other sexual issues. I did email him the night after bringing that one topic up to get reassurance that he didn't think negatively of me, and he gave me that reassurance.

I agree with the suggestions to write things down or email if you have trouble talking about them. I recall someone else doing something where they had a drawing of the human body and just circled or pointed to where something happened.