The button is too small to drum on it with two fingers, I guess?
Depending how touch friendly the game is supposed to be, the mini-game could be different. There are minis that are ridiculusly easy on touch, but hard with mouse.
And there is of course the itsy bitsy mobile phone displays. You can't see the screen with your hand in the way, tapping stuff. An outrage for a porn game ;-)
You could cheat and connect a mouse to your Android phone. But I think it will not give more click events to the app. If you mush with many fingers, it tries to read a gesture or interprets it as a single tap. I tried with some app and that one registers only two clicks, when I alternate between tap and mouse click.