What is a Jog Strap?

I am convinced that the Jog Strap is a real product as I can find realistic images of it on the interwebs. However, there's no place to actually purchase them so I don't know. What I do know is that I wish I could witness a Jog Strap in action on the streets of Missoula.

In case you missed the commercial on The Tonight Show with Jimmy Fallon.

And here's one that a very dedicated woman knitted for her friend, I love that he immediately tries it on. Because who doesn't want to get repeatedly smacked in the sack while jogging?