Any doctor, nurse or tech that has to handle male genitals in their daily work will have seen men accidentally get erect and even ejaculate, hundreds of times. This would not be stimulating to them, just something the patient's body does, and they would hardly note it. You are never going to know if the tech's actions were excessive unless you ask another ultrasound tech (or possibly a doctor) and can bring yourself to explain what happened back then, and see if that is standard procedure for taking this kind of picture. Also, I'd guess that if there was a tech out there who was getting his jollies by stroking guys, he would be picking on the hot 20-year olds, not guys in their middle years. This makes it seem a little more likely that he wasn't particularly trying to get you erect, or if he did, he wasn't interested or maybe wanted the penis out of the way or a muscle to be tight. I agree you have the right to wonder, and I would wonder too in your position. But frankly, there seems to be little profit in asking anyone in the health world because even if they did think a fellow medical person did something improper, medical people tend to close the circle and try not to get each other into trouble.