OTG stands for "USB On-The-Go."
OTG is a "specification that allows USB devices ... to act as a host, allowing other USB devices ... to be attached to them. ... For instance, a mobile phone may read from removable media as the host device, but present itself as a USB Mass Storage Device when connected to a host computer."
Translation: An OTG drive can be plugged into a PC and then into a phone.
I had never played with these until I came across this one.
Then I couldn't find anything to do with it!
But recently I found a good use case for it.
I had ripped Flash Boys: A Wall Street Revolt to mp3s and wanted to move it to my Nexus 5.
I put the USB A end into Trump and dragged the mp3s to it. I ejected it and took it over to the phone.
When I plugged it in I got this in the Notification area.
I tapped on "PNY USB drive" and got this.
I long tapped on "Michael Lewis" and then pulled down "...".
I tapped on "Copy to ...".
And I was able to copy the folder to the phone.
To eject it, I pulled down the notification shade again, opened the Settings and ejected it.
If it would just fit on my key chain I'd use it a lot more. By the way, it did get hot while plugged into the phone.
Oh, there's one for the iPhone too with a slight Apple tax.