>I wondered about the expression "apparantly not wrapped too tight", which I did not know, but which is very suggestive. Is it in common use?

It is very suggestive, but it is one I have never heard before.
One expression I really liked in this vein was in the Stephen King movie of a couple years ago (it starred Tom Hanks but I cannot for the life of me remember the title however). A sheriff commenting on someone who was being hauled of to the asylum said, "His cheese slipped plumb off his cracker."

It is interesting to me number and variations of such expressions which, although one might not have heard before, are immediately understood.