The act of giving oral sex while playing Call of Duty 4 or Call of Duty Modern Warfare 2.
John had just waited in line at midnight madness in order to get Modern Warfare 2 but his girlfriend wanted to hang out with him so he allowed her to give him a Soap Mactavish.
one who is adept at avoiding bars of soap when thrown at them
Tim is an excellent soap dodger and stayed in the game while his teammates were pummeled with bars of soap. He must have learned his techniques from being a three-time MVP of the more traditional sport dodgeball.