Summer's End Mystery

My son's retainer ended up in the neighbor's yard today.

Just how does that happen???

I can't even imagine, my imagination now being shackled to adult sensibilities.  Such sensibilities would include:

-- You don't hang your head over the fence, face down, with your mouth open.

-- You don't wind up and, with mouth open, swing your head violently in one direction so as to hurl said retainer out of your mouth and clear over the fence.

-- You would never see the occasion to take it out and throw it anywhere.  Ever.

Of course, my son emphatically denies the occurrence of any of these things.

But how else could this happen?  

Since the culprit, the purveyor of such mysteries, the nine year old with a day-glo orange retainer is claiming complete innocence and ignorance in this matter, I am only left to wonder

. . . and count the hours until school tomorrow.