If I can explain a little better.....the part that is adhered to the tip of the glans I don't mess with. But sometimes little bits of "poop" get stuck on the end and the foreskin droops down, catching it in there. I can't very well leave fecal matter in the folds of my son's penis, or bathe him after every diaper change. The overhang slides freely. Like a "loose sock"(

DH will love that visual).
DH and I talked about this at great length the first time he changed DS's diaper. Silly me, I assumed as an intact adult, he would know little foreskins don't retract. But this is something I don't supose mothers discuss with their sons. So if he retracted at a young age, I can understand his ignorance.