I had a testicular ultrasound done recently. The test took about 15 minutes. During the test at about 10 minutes in I felt as if I was about to ejaculate. I did not have an erection at the time but when this started to happen I started to become erect. I asked the tech if she could stop for a minute but she said she was almost done and not to be embarrassed about an erection. Just as she was explaining that this was ok. I ejaculated. This was very embarrassing. Should she had stopped when I asked her to or was she just used to males getting erections during this procedure and thought nothing of it, not realizing the reason I wanted her to stop was because I felt I was about to ejaculate. I know this is not very common but does this happen and why would I have this happen when I was not sexually stimulated in any way. I don't know how this happened so suddenly.