dual-fist
To use both hands in the same activity, either in weapons (dual-wielding is a better term) or in a sexual manner (that is where the fisting comes in.
Player 1: "I'm dual-fisting all of you! I'm the greatest!"
Player 2: "...Faggot..."
Player 2: "...Faggot..."
Dual fist action
Dual fist action refers to rubbing the meat with both hands. Generally speaking if you can fit both hands on your dick it is very large.
Will: I get that dual fist action on every night.
Kyle: I can only get that single fist action.
Kyle: I can only get that single fist action.