Where's my whistle??

I was on prac teaching a sports lesson. I had a whistle around my neck which I took off but was still holding.
I explained the game and then blew the whistle to start. Not realizing it was no longer around my neck, I dropped the whistle and it unknowingly fell to the ground.

After a few minutes I felt for my whistle to signal stop but it wasn't there.
wierd. where's my whistle?
I looked all around and eventually saw it on the ground. How did it get there? Oh well.

I regrouped the kids and blew the whistle to start again.
Once again it unknowingly fell to the ground. Once again I felt for it to blow stop and it wasn't there. and once again i found it on the ground.

I thought I was going crazy.
I repeated this blow, drop, search procedure many times throughout the lesson until one time out of the corner of my eye I saw it dropping to the ground from my mouth.
In front of the kids I said, "Oh THAT's what's happening!"