Madden NFL 09

Play on Rookie difficulty, any teams. Pause and select Settings, Gameplay, Game Rules, and slide Offside to 0.

On defense, move a player next to the QB. Avoid the offensive players to prevent encroachment pentalties.

After the snap, hold LT for easier sacks.

Also, if you save after the game, the penalty settings will also be saved.

The easiest way to earn this achievement is to start a game, doesn't matter who is playing, and once the game starts, press start to go into the pause menu, settings, game settings and customize the penalties to 0.

Then, when you're on defense, use the same player and move him next to the QB of the opposing team and wait until the hike. If you're close enough the player will sack the QB automatically.

Use this method for the 6 by the same player in a game as well.

Credit to BillyxMac for the video. I used the Patriots against the Dolphins since the Patriots are a high team while the Dolphins are lower. When you move behind the guy make sure you do it fast and not touching ANYONE or your going to keep getting penalties called on you which is going to take a lot longer.