What ordinary activity would be done completely differently if you had 3 hands?

I'd have a hand to play with my balls while I jerk off and finger my asshole

There was a 2 player Terminator arcade shooting game. Your options were a pistol each or someone could use the shotgun. I would use two lists but if I had a third arm I'd be able to use the shotgun instead of a pistol. Mundane I know but it was the first thing to come to mind.

Masturbation. One hand on dick, one on prostate, one on the throat. Or if you're female, one hand in vagina, one on clitoris, one hand on nipple. Something like that.

Is the arm included?

Edit: Grammar