It is a much more invasive pat-down that involves touching, probing, and feeling your body, including your genital area, to determine if
you are concealing something.
It is what the Transportation Security Administration (
TSA) will do to you if you opt-out of the full body scanner, which takes a naked picture of you, before boarding an
airplane.
TSA Agent: "If you
won't let me to take a naked picture of you, then I'm going to rub your
penis."
Child: "That would be sexual assault."
TSA Agent: "Nonsense, it's just an enhanced patdown. Now spread your
legs."