This simple file would be a trigger, which should be self-triggered, designed specifically for men.
The overall idea of this file is a trigger phrase, such as "Nothing between my legs" or "Nothing between your legs", that would numb your genital region until it feels like there's nothing between one's legs but smooth skin, and no amount of stimulation would abate the feeling, like brushing against it or feeling it (Obviously you could reach down and still feel it there, but that's not the point). It could be reversed by the phrase "There's something between my legs", or the like.
The purposes of this file are numerous. I personally have a fetish for not feeling anything between my legs. It could be a training file for those who are going to be castrated or have SRS, what it would feel like to not have a penis between one's legs. This file is multipurpose, and that's what it should be.
Anyone else like this idea?