Cough test

Ankit goes to the doctor for his five year checkup.

Since he is a boy, the doctor asks him to drop his pants and gives him the "cough" test. While the doctor is still holding on, Ankit says: "I know what you are doing!".

"What do you think I am doing", the doctor asks, partly shocked, partly surprised by the assertion.

"You are checking my kidneys", Ankit quickly responds. Of course.