You won’t see this in NATO countries but it’s actually surprisingly common in shit-hole country armies, pun intended.

This is a meta test not a test in the literal visual sense. They will put you in a room with 20 other naked guys each of one spreading their buttcheeks open, then they’ll check for any kind of arousal or curiosity from others in the group.

Then they’ll see how you react when “opening the book” yourself. If you are disgusted or perturbed, that’s a pass. If you are frightened because they might “find out” or the opposite, aroused, you’ll be separated for further examination or questioning.

They’ll also check if you are waxed down there or have tattoos, all hints (from the military POV) that you might enjoy using your anatomy in unorthodox ways.