With an edited lineup full of speedy players, play a game with max slider for Baserunner Speed, and the lowest setting for Fielder Run Speed, Fielder Reaction, and Fielder Arm Strength. Decrease the individual outfielder stats for whichever team you play against. I suggest the Yankee's or Dodgers since you may already have those teams edited to play bad.
*thanks Reys813fan for the following tip*
While at bat, knock a line drive to the outfield and quickly hit start and change teams. You will now control the defender and using you can dive and miss the ball. Quickly switch back teams and you should get an inside the park home run. Play in a park with a deep outfield like Polo Grounds, Fenway Park, or Minute Maid Park.
Beat LA and Yankees 'Inhale Deeply Through The Mouth' can not be unlocked if you switch teams.