Have you ever played thumb fight against your friend? If you have played so, it will not be hard for you to play this game. In this game, you will control the one thumb and your friend control the other thumb. If you catch the thumb of your friend while he/she is attacking, you can decrease his/her health. If you catch the thumb of your friend, hold it for a while to give more damage. The one who finishes the opponents health first, wins the game.
Have fun!