Fake being sick at Army service

One interesting story, when I was 19, joined the Army and had an infection in my stomach, vomiting and diarrhea, the troop doctor pushed his finger into my bum as well. Maybe he didn't trust me, but finally he said that I was ill indeed. I know from other comrades that some wanted to fake being ill, and also got the finger in their butts.

Does anyone have similar experiences? Does anyone tried to fake being sick at the troops?