How to replace a finger for tapping on a smartphone?

Question

Mobile devices

I would like to create a small device "Emulator of clicks or actions" for a smartphone, something like a bot for games (just for sport and fun).
The question is: What can replace the finger? How can a robot arm press on a smartphone screen so that the sensor responds to pressing?
Please do not offer - a piece of meat or a cucumber. I would like something more elegant and not to spoil, and not rotten :)

Answer 1

So where are the suggestions?