Just to parrot what others have said repeatedly already, you've nothing to be ashamed of, it happens.
I am going to tell you a story of something that happened last year to me.
I had to get a somewhat invasive medical diagnostic test done. I had been dreading this for about 10 years, what could be so bad? A colonoscopy, that's what. Basically after two days, and a literal gallon of laxatives, I had to walk into a hospital ward to have a 6 foot long colonoscope put up my backside. I am only 5' 11". For me that really wasn't the worst part.
I am a prudish Catholic. The idea of having to bare my arse for a doctor and his nurse, not cool. I found out a disconcerting fact that day, I don't know how to tie a hospital gown behind myself. I figured it out when I went to make the last trip to the loo. Stood up and the gown didn't follow. Naturally the privacy curtain was open. Oh and every nurse was female, young and under 30.
The reaction I got was about what I expected, not one of them evem batted an eye. Why? Because I am not the first anatomical specimen to flash the colonoscopy ward.
After the exam, any lingering concerns I had left after the procedure was done, one of the nurses approached me to ask if I would call her after I take the trip to the loo before they discharge me, because she needs to have a look.... In the bowl. After, she thanked me for not arguing. Just needs to be done.
Professionals. Nurses, doctors and therapists. They went to school for many years spent thousands and thousands of pounds countless hours studying, likely having to end friendships and relationships to make time to be competent in their chosen field. Learned everything they could. Not to judge you, but to help you. That really is what your therapist wants.