I was kinda being facetious, more of an F U finger than a serious suggestion.

In all honesty, I can’t see how this would be useful - either you’d have to use a finger that wouldn’t look natural, and give the game away, or use a thumb or index finger and constantly have to re-load your phone due to accidentally wiping it!

The print of the middle finger, one might suggest

Much like Israel used US missiles to kill people in Palestine, no?