Doctor's test

I'm 14. One day at school we were going to get a full check up in the doctor's office for the entire class. So one by one we were going inside for the check-up.

The doctor appeared to be a woman at her 30s. She told me to strip, so I got all embarassed. She was touching me from top to bottom, including my thing. When she touched it I got hard which made me more embarassed.

All ok so far, but after a while she told me that there's a test based on taste that she could tell if I'm healthy. I said, well ok.. Then she started licking my thing for 10 to 20 seconds and when se was done she said that I'm healthy.

I just want to know, is there any test like that?
Thanks