Dear Prosperity,
I got mine caught in a zipper too when i was just 7 or 8 and it was a living hell because it happened in the middle of the night and i was staying over as a guest in someone's house. gosh i made such a scene... luckily the elders in the house were able to remove the zip without any pain.. but i was left blushing for days.. :) since then ive had no accidents, but ive gained a whole new respect for zippers and the importance of underwear... :) i think anyone who has had a similar experience would take care in the future as such things happen.
what is strange to me is that instead of teaching kids how to properly clean what they have, health class instead recommends to cut it off. ****sigh****
anyways all this aside (sorry to ramble), i do hope that your son will confide in you and vice-versa. maybe if there are other issues which are yet unclear to you right now, these should be explored yes? I think underneath this "symptom" you are slowly unraveling something deeper. Go on. This is the right path.
love love love