Looks like the PS4 vs Xbox One battle is turning one-sided as far as sales victories are concerned....
The Witcher 2 Arm Wrestling Guide
You can begin this mini game by finding an opponent and choosing appropriate dialogue option. Before you sit at the table to begin the contest, you will need to put a bet. After the match begins, you must slam your opponent’s hand to the table in order to win.
Keep the fist cursor within the yellow bar that will be moving beneath your opponents. You move the cursor using the mouse. The winner takes all the money that was bet earlier. Avoid dwarves, they are very good at Arm Wrestling and will prove to be toughest of opponents.
How To Win Arm Wrestling
When you have begun the arm wrestling, you will see a long grey bar, a shorter orange bar, and a circled cursor on top of it. You need to keep the cursor inside the orange bar. As the game progresses, the orange bar will get shorter and shorter as Geralt grows tired.
Your goal is to keep the cursor inside so long as to allow orange bar to reach the right side. If you do manage that, you win. You don’t have to do anything to move the orange bar to the right; it moves automatically, but may shift left if you can’t keep the cursor inside, for even a small period of time.
It’s a bit tricky but you do earn double, so why sweat?