I am so glad I am a woman. If there was a chance I could loose my genitalia by zipping my privates in my pants I would never ever wear pants again. Men don't have a choice. Unless they want to wear button flies for the rest of their lives.
My 5 yr old had the terrible habit of not wearing underwear. Aside from daily undie inspection I couldn't really force the issue. I would just discover it when I did his laundry. Or rather I would not discover them. That all changed recently with a little episode right out of Hollywood, specifically There's Something About Mary.
He was wearing pants that were a weeeee bit too tight. When he couldn't get his pants zipped up he asked me to help him. Each time I got it half way up he would bend in half and pull away from me. I finally figured out he was trying to protect the family jewels. So I called the Dh in to figure out how to zip him up without damaging anything. Upon finding us in the situation the Dh had to explain to my 5 yr old how he could zip his parts right off if he weren't careful. Then in a quick zip his pants were up and the Dh let out a gasp.
No, he didn't zip up anything. He was just messing around. But it proved a point to our 5 yr old, who now has been diligently wearing underwear ever since. All it took was a little story about Pork and Beans...and a gasp.