Since you seem to be a medical expert on this phenomenon, let me ask you - is it possible to fall on an object and have it insert itself somewhere? It seems to me that you’d just fall on it and smash it, or it might bruise or cut you, but just to fall on something and have it disappear? Seems unlikely.
So why bother with the elaborate stories? I mean, who, especially a vicar, is hanging curtains while naked?? There’s no way he thought people would believe him, so he should just admit he’s a freak and let the medics do what they have to do. : )
My opinion is "No." But stranger things have happened. Usually when that does happen, it's something sharp and it tears the rectum. I've seen metal fence stakes, tent stakes etc. do that.
Maybe "Mythbusters" would tackle this one.
There is this classic vid: Elephant Sits on Man’s Head.....http://www.youtube.com/watch?v=NJHgOnQ6WEk